Wrestling with color management

X
Posted By
xerj
Dec 9, 2004
Views
592
Replies
19
Status
Closed
There are so many questions, but I’ll start with the first:-

I’ve profiled my monitor using Adobe Gamma. When I select Proof Colors with Monitor selected, the results look pretty muddy and horrible. What exactly is this telling me? Shouldn’t it not change as the monitor profile is what is used as an output at all times anyway (Adobe 1998 RGB is the working space, although some embedded profiles are sRGB)?

Sorry if the question doesn’t make sense.

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W
Waldo
Dec 10, 2004
xerj wrote:
There are so many questions, but I’ll start with the first:-
I’ve profiled my monitor using Adobe Gamma. When I select Proof Colors with Monitor selected, the results look pretty muddy and horrible. What exactly is this telling me? Shouldn’t it not change as the monitor profile is what is used as an output at all times anyway (Adobe 1998 RGB is the working space, although some embedded profiles are sRGB)?

Sorry if the question doesn’t make sense.

What kind of images are you viewing? Photographs?

Hmmm, just tried out myself, when choosing your monitor profile, it looks murky indeed. On the other hand, why would you want to proof an image for the same device, you’re already looking at? Normally, you want to softproof a printer or other device. Try to change it to e.g. your printer profile (otherwise try Euroscale or SWOP) and see the difference. This way, it approximately (!) looks like if it was printed…

Waldo
X
xerj
Dec 10, 2004
Yup, I’m viewing photos.

The reason why I wanted to proof to the monitor is because one tutorial I can’t find now said to check that it looks good doing this, although I probably understood it wrong. Thinking about it now, I suppose it shouldn’t actually look correct when monitor proofed, because if I’ve grasped it correctly what color management is supposed to do is remap an image so that the biases of the monitor are neutralised.

This is a subject I’ve put off coming to terms with for too long.
MG
m.golner
Dec 13, 2004
The question makes sense, I’m not sure that this answer will, however. I’ve wondered about this for a couple of years, and over the past several months have put a lot of effort into understanding what’s going on. I either understand it better (but not completely) now, or am simply more delusional, but here’s an attempt to explain it.

Before we get into the nitty grits, we need to do a couple of things. The first is a freehand sketch to show the relationship between the color spaces involved, namely Adobe RGB 1998, and Monitor RGB. Adobe RGB is of course fixed, and Monitor RGB depends on your particular monitor and its calibration, but the idea should still be valid.

First, draw a triangle with each side about equal in length, and rotated so the base is about 30 degrees counterclockwise from horizontal, i.e. lower right corner tipped up. Label the lower left corner as B, the right corner as R, and the top corner as G. Triangle RGB represents Adobe RGB space in CIE Yxy coordinates, one of several common ways to look at color spaces. Now, starting at G, go along line GR about 25% of the way toward R and put another point. Label this point G’. Triangle RG’B represents a typical monitor color space. Note that this is only a very rough representation, but it will help in understanding some of the things that happen. This is a two dimensional representation of a three dimensional phenomenon, so it holds true enough to show a concept, but breaks down if you try to use it too precisely.

The next thing is simply a configuration setting in Photoshop. I don’t know what version you are using, but this is based on PS7. In the menu bar, go to Window, and place a check by Info. Then in the Info Palette, click the little triangle at the top right and select Palette Options, where you should set First Color Readout to Actual Color, and Second Color Readout to Proof Color. This will let you see both the RGB value from the file, and if you have selected Monitor RGB as the proof space, the RGB value that is actually being sent to your monitor, for any point in a file your cursor hovers over. It can be really enlightening.

Next, again in Photoshop, again in the Window menu, place a check by Color. In the color palette, make sure the foreground (upper left overlapping square) is selected (double line outline). In the Tool Palette, select the Paint Bucket tool (make sure Tools is also checked in the Window menu).

Finally, open 2 new files, Contents set to White. They should be small, like 300×300 pixels. We’re just going to fill them each with a single color. I assume that you have Adobe RGB set as your default working space, so the files should end up created and tagged as Adobe RGB color space.

As we start going through things, there are two ideas to keep in mind.

The first is that as you look at the two color space triangles, you notice that there is a large area where they overlap, and another smaller area OUTSIDE of Monitor color space but WITHIN Adobe RGB. Behavior is different in each of these two areas. Let’s just set that thought aside for the time being.

Second is that in Photoshop there are different ways to set up the Monitor Proof space, and how you do it will determine the effect you get. Briefly, the first way is by selecting View – Proof Setup, then scrolling down to Monitor RGB. The second is by selecting View – Proof Setup – Custom. Then in the Proof Setup dialog box, you open the Profile dropdown list and select your monitor’s profile. This is (or should be) the same profile that Photoshop uses by the first method, BUT, you also get control over whether to Preserve Color Numbers, and if you choose not to, you get control over rendering intent. By comparison, when you use the first method, Photoshop (I’m 99% sure) locks you in to Preserve Color Number mode.

The difference here is that the first method simply passes the color numbers through from one color space to another, while the second method attempts to convert the color numbers so that the color looks the same as you move from one space to the other.

For now, select each of your new files in turn and set the proof space to Monitor RGB using the second method. Uncheck Preserve Color Numbers and select the Intent of your choice. I like Relative Colorimetric Intent w/ Black Point compensation as a starting point.

We’ll start by looking at a point that lies comfortably within both the Adobe RGB and the Monitor RGB color spaces. Let’s work with Adobe RGB 200,100,200, which I would call a mid-tone magenta. Go to the Color palette and enter the color numbers R: 200, G: 100, B: 200. You should have a magenta in the Foreground color box of both the Tools and Color palettes. Then click the title bar of one of the new files you created, to select it, then click in the white space, and the paint bucket should fill the file with that color. Leave the cursor in the file area, and the Info palette should show that the Adobe RGB color value is 200,100,200 (left side) and the Monitor RGB space value (for MY monitor) is 227,97,202 (right side). Your value is most certainly bound to be different than mine. The important thing is that the Monitor space color number is different than the Adobe space color number in order to give the same appearance. If you toggle Proof Colors on and off (Ctrl-Y) you should see no change in color. (As an aside, maybe this is the check on the quality of your monitor profile you referred to in your reply to Waldo. If you have a poor profile, you might see a visual change here.)

By way of contrast, select the second of your new files and dump the same 200,100,200 color into it. Next, set proofing for this file to Preserve Color Numbers. Now you will see in the Info palette that both Adobe RGB and Monitor RGB values are 200,100,200, and as you toggle from Adobe RGB space to Monitor RGB space, you will see the color change, to a more blue appearing hue (actually more cyan, I think). Again, depending on your monitor’s profile, you may get different results.

Let’s try to rationalize this with what we see on the two color space triangles we drew earlier. First it’s important to understand that we have drawn these two color spaces imposed on a CIE Yxy coordinate system, and that we should consider the CIE space to be absolute. It is a device independent space, and each point on the paper is IN ACTUALITY a DIFFERENT, UNIQUE color. Hence, G and G’ are different colors, for example, even though they are both 0,255,0 in their own space. Forget about how our devices render the numbers. Different points on this plot are different colors, period.

Now let’s look at our 200,100,200 magenta. If we consider it’s location in the Adobe RGB space, i.e. triangle RGB, it will fall about midway between R and B, then about 20% of the way up toward G. By comparison, in the Monitor RGB space, i.e. RG’B, it will likewise fall about midway between R and B, but then about 20% of the way up toward G’. These are clearly two different points on the paper, so we have the color shift if we Preserve the Color Numbers. However, if we let the Adobe Color Engine do it’s color management thing, it will convert the 200,100,200 magenta in Adobe space to 227,97,202 (my monitor) to give the same appearing color.

At this point in time it may be worth considering that all of this is done ‘on the fly’, as it relates to the monitor’s displaying of colors. Adobe doesn’t change file color numbers to effect an accurate display rendering. The scenarios we have just considered are all done ‘in the back room’. We can think of it as the Actual color number is what’s in the file, and the Proof color number is what’s being faked to the monitor to get it to look right.

Here’s another way to look at this, and it might be a bit more tied to something we can physically imagine. If you were to take the file with the 200,100,200 magenta in it (tagged with Adobe RGB space), and CONVERT the profile to Monitor RGB (Image – Mode – Convert to Profile, then select your Monitor profile, and select relative colorimetric, bpc, etc), then save it, then open it in another application that doesn’t have color management, it should look like the the actual 200,100,200 color in Photoshop. Note that the colors will have been changed in the file to color number 227,97,202 (again, my monitor). If however, you ASSIGN the profile to Monitor RGB (Image – Mode – Assign Profile, then select Monitor profile), the color values in the file stay as 200,100,200, but the file is tagged with Monitor RGB as the profile. If you open this file in a color unmanaged app, the file will appear as the darker, more cyan version of magenta. Likewise, if you STRIP the profile (Image – Mode – Assign Profile, then select Don’t color manage…), the values also stay at 200,100,200, and the file will look like the darker color in an unmanaged app. If you are running Win XP (or Me?), an easy way to open the files in an unmanaged app environment is to select the file in explorer, right click it, then select preview. This opens it in the Picture & Fax Viewer Applet, and you can size it really small, and drag it over your Photoshop window for side-by-side comparison.

So in a nutshell, what we’ve said so far is that you shouldn’t worry about what Photoshop does internally to display a color correctly. That just happens. What Proofing to your monitor space does is to give you a look-see at what a file might look like in another app that doesn’t use color management, or what it might look like in an app that uses Monitor RGB as it’s working space. I don’t use Image Ready (haven’t loaded it so I can’t try this), but I’m under the impression that Image Ready uses Monitor RGB as it’s working space.

So that was a discussion of the area where the two color spaces overlap. Now let’s take a quick look at what’s different in that area defined in the color space triangles sketch as triangle BGG’, i.e. the area OUTSIDE of the monitor’s color space.

If you think about what this area represents, it’s a portion of the space where you can create a color in Adobe RGB that your monitor can’t display. Let’s check that out by going to the the Color palette and setting a color of 0,255,0. You should have a bright green in the Foreground color box of both the Tools and Color palettes. Then select one of your files and click inside of it to fill it with the green. Leave the cursor in the file area, and the info palette should show that the Adobe RGB color value is 0,255,0 and the Monitor space value is also 0,255,0. This is basically saying that we have created a green in Adobe RGB that is too bright for your monitor to display, but the monitor is doing its best by giving the brightest green it can.

Lets now cut back on the Adobe space color a bit and see what happens. Again a reminder that your monitor and mine have almost zero chance of agreeing here, but the effect should be similar. Go back to the Color palette and set a 50,255,50 green. Select the second new file and click the file space to fill it. For my monitor profile, the info palette shows 50,255,50 for the actual color and still 0,255,0 for the Monitor color.

In other words, we have dulled down the green in Adobe space a little, but it is still brighter than the monitor can display, so the monitor is still maxxing out on green. You can Toggle Proof (Ctrl-Y) for a visual confirmation. If I go much above 50 blue in Adobe space, I start to see blue going up in the proof space, which to me says that I’m moving into the area where the triangles overlap. You can play with different proof settings here to see if you can rationalize the details of what you see, and compare them with the results from the ‘in gamut’ magenta examples.

So the summary on this BGG’ area is that you can create theoretical colors in Adobe RGB space that your monitor can’t achieve. Whether this represents a problem I can’t say, but probably not a major one, if at all. Is there a green in nature that’s so bright that it fits into this regieme? If so, can film truly capture it? Can a scanner capture it? A digicam? Can a printer print it? All things to think about.

One final thought. I think you are on the right track in calibrating your monitor. Unless it’s pretty accurate, your chances of implementing a successful color managed workflow are significantly hampered. Some say it’s hopeless without a ‘perfect’ monitor calibration & profile. I don’t know if it’s that black & white.

My personal experience is that I spent a LOT of time trying to get my monitor in calibration using Adobe gamma. I feel it certainly improved things from before I used it. I also checked it with a myriad of visual aids available on the web, and I was pretty confident that I had it ‘right’.

Then I had the chance to use a colorimeter, and do a ‘professional’ grade calibration & profile. All I can say is WOW. The color of my wallpaper changed noticeably, and the neutral grey background used by Photoshop (and other apps) suddenly really looked grey. I had previously thought it was grey, but as soon as I did the instrument calibration and saw the ‘new’ grey, I realized that it had had a sorta reddish brown cast.

I also found that the 1000 or so film scans that I had done over several months prior to the ‘real’ calibration needed to be redone. Fortunately, it was a ‘constant offset’ situation, so I could do a Photoshop action to add some contrast, remove some brightness, and add some saturation, and batch bang them all out with minimal pain.

The point here is that you are doing the right thing by paying attention to your monitor. And the best solution is not a freebie, so each person needs to consider his/her circunstances and do the trade-offs. But for what it’s worth, the best technique that you can personally justify will pay dividends.

Best of luck in your efforts to understand color management. Sorry this got so long.

xerj wrote:
There are so many questions, but I’ll start with the first:-
I’ve profiled my monitor using Adobe Gamma. When I select Proof Colors with Monitor selected, the results look pretty muddy and horrible. What exactly is this telling me? Shouldn’t it not change as the monitor profile is what is used as an output at all times anyway (Adobe 1998 RGB is the working space, although some embedded profiles are sRGB)?

Sorry if the question doesn’t make sense.

H
howldog
Dec 13, 2004
On Mon, 13 Dec 2004 20:32:31 GMT, "Mike G."
wrote:

My personal experience is that I spent a LOT of time trying to get my monitor in calibration using Adobe gamma. I feel it certainly improved things from before I used it. I also checked it with a myriad of visual aids available on the web, and I was pretty confident that I had it ‘right’.
Then I had the chance to use a colorimeter, and do a ‘professional’ grade calibration & profile. All I can say is WOW. The color of my wallpaper changed noticeably, and the neutral grey background used by Photoshop (and other apps) suddenly really looked grey. I had previously thought it was grey, but as soon as I did the instrument calibration and saw the ‘new’ grey, I realized that it had had a sorta reddish brown cast.

what was the software you used?

been thinking of maybe doing this myself.
MR
Mike Russell
Dec 13, 2004
Mike G. wrote:
The question makes sense, I’m not sure that this answer will, however. I’ve wondered about this for a couple of years, and over the past several months have put a lot of effort into understanding what’s going
on. I either understand it better (but not completely) now, or am simply more delusional, but here’s an attempt to explain it.
Before we get into the nitty grits, we need to do a couple of things. The first is a freehand sketch to show the relationship between the color spaces involved, namely Adobe RGB 1998, and Monitor RGB. Adobe RGB is of course fixed, and Monitor RGB depends on your particular monitor and its calibration, but the idea should still be valid.
First, draw a triangle with each side about equal in length, and rotated
so the base is about 30 degrees counterclockwise from horizontal, i.e. lower right corner tipped up. Label the lower left corner as B, the right corner as R, and the top corner as G. Triangle RGB represents Adobe RGB space in CIE Yxy coordinates, one of several common ways to look at color spaces. Now, starting at G, go along line GR about 25% of the way toward R and put another point. Label this point G’. Triangle RG’B represents a typical monitor color space. Note that this is only a very rough representation, but it will help in understanding some of the things that happen. This is a two dimensional representation of a three dimensional phenomenon, so it holds true enough to show a concept, but breaks down if you try to use it too precisely.

The next thing is simply a configuration setting in Photoshop. I don’t know what version you are using, but this is based on PS7. In the menu bar, go to Window, and place a check by Info. Then in the Info Palette, click the little triangle at the top right and select Palette Options, where you should set First Color Readout to Actual Color, and Second
Color Readout to Proof Color. This will let you see both the RGB value from the file, and if you have selected Monitor RGB as the proof space,
the RGB value that is actually being sent to your monitor, for any point
in a file your cursor hovers over. It can be really enlightening.
Next, again in Photoshop, again in the Window menu, place a check by Color. In the color palette, make sure the foreground (upper left overlapping square) is selected (double line outline). In the Tool Palette, select the Paint Bucket tool (make sure Tools is also checked in the Window menu).

Finally, open 2 new files, Contents set to White. They should be small, like 300×300 pixels. We’re just going to fill them each with a single color. I assume that you have Adobe RGB set as your default working space, so the files should end up created and tagged as Adobe RGB color space.

As we start going through things, there are two ideas to keep in mind.
The first is that as you look at the two color space triangles, you notice that there is a large area where they overlap, and another smaller area OUTSIDE of Monitor color space but WITHIN Adobe RGB. Behavior is different in each of these two areas. Let’s just set that thought aside for the time being.

Second is that in Photoshop there are different ways to set up the Monitor Proof space, and how you do it will determine the effect you get. Briefly, the first way is by selecting View – Proof Setup, then scrolling down to Monitor RGB. The second is by selecting View – Proof Setup – Custom. Then in the Proof Setup dialog box, you open the
Profile dropdown list and select your monitor’s profile. This is (or should be) the same profile that Photoshop uses by the first method, BUT, you also get control over whether to Preserve Color Numbers, and if you choose not to, you get control over rendering intent. By comparison, when you use the first method, Photoshop (I’m 99% sure) locks you in to Preserve Color Number mode.

The difference here is that the first method simply passes the color numbers through from one color space to another, while the second method attempts to convert the color numbers so that the color looks the same
as you move from one space to the other.

For now, select each of your new files in turn and set the proof space to Monitor RGB using the second method. Uncheck Preserve Color Numbers
and select the Intent of your choice. I like Relative Colorimetric Intent w/ Black Point compensation as a starting point.

We’ll start by looking at a point that lies comfortably within both the Adobe RGB and the Monitor RGB color spaces. Let’s work with Adobe RGB 200,100,200, which I would call a mid-tone magenta. Go to the Color palette and enter the color numbers R: 200, G: 100, B: 200. You should have a magenta in the Foreground color box of both the Tools and Color palettes. Then click the title bar of one of the new files you created,
to select it, then click in the white space, and the paint bucket should fill the file with that color. Leave the cursor in the file area, and
the Info palette should show that the Adobe RGB color value is 200,100,200 (left side) and the Monitor RGB space value (for MY monitor)
is 227,97,202 (right side). Your value is most certainly bound to be different than mine. The important thing is that the Monitor space color number is different than the Adobe space color number in order to give the same appearance. If you toggle Proof Colors on and off (Ctrl-Y) you should see no change in color. (As an aside, maybe this is the check on the quality of your monitor profile you referred to in your reply to Waldo. If you have a poor profile, you might see a visual
change here.)

By way of contrast, select the second of your new files and dump the same 200,100,200 color into it. Next, set proofing for this file to Preserve Color Numbers. Now you will see in the Info palette that both Adobe RGB and Monitor RGB values are 200,100,200, and as you toggle from Adobe RGB space to Monitor RGB space, you will see the color change, to
a more blue appearing hue (actually more cyan, I think). Again, depending on your monitor’s profile, you may get different results.
Let’s try to rationalize this with what we see on the two color space triangles we drew earlier. First it’s important to understand that we have drawn these two color spaces imposed on a CIE Yxy coordinate system, and that we should consider the CIE space to be absolute. It is
a device independent space, and each point on the paper is IN ACTUALITY
a DIFFERENT, UNIQUE color. Hence, G and G’ are different colors, for example, even though they are both 0,255,0 in their own space. Forget about how our devices render the numbers. Different points on this plot are different colors, period.

Now let’s look at our 200,100,200 magenta. If we consider it’s location
in the Adobe RGB space, i.e. triangle RGB, it will fall about midway between R and B, then about 20% of the way up toward G. By comparison,
in the Monitor RGB space, i.e. RG’B, it will likewise fall about midway between R and B, but then about 20% of the way up toward G’. These are clearly two different points on the paper, so we have the color shift if
we Preserve the Color Numbers. However, if we let the Adobe Color Engine do it’s color management thing, it will convert the 200,100,200 magenta in Adobe space to 227,97,202 (my monitor) to give the same appearing color.

At this point in time it may be worth considering that all of this is done ‘on the fly’, as it relates to the monitor’s displaying of colors. Adobe doesn’t change file color numbers to effect an accurate display rendering. The scenarios we have just considered are all done ‘in the
back room’. We can think of it as the Actual color number is what’s in
the file, and the Proof color number is what’s being faked to the monitor to get it to look right.

Here’s another way to look at this, and it might be a bit more tied to something we can physically imagine. If you were to take the file with
the 200,100,200 magenta in it (tagged with Adobe RGB space), and CONVERT the profile to Monitor RGB (Image – Mode – Convert to Profile, then
select your Monitor profile, and select relative colorimetric, bpc, etc), then save it, then open it in another application that doesn’t have color management, it should look like the the actual 200,100,200 color in Photoshop. Note that the colors will have been changed in the file to color number 227,97,202 (again, my monitor). If however, you ASSIGN the profile to Monitor RGB (Image – Mode – Assign Profile, then select Monitor profile), the color values in the file stay as 200,100,200, but the file is tagged with Monitor RGB as the profile. If you open this file in a color unmanaged app, the file will appear as the darker, more cyan version of magenta. Likewise, if you STRIP the
profile (Image – Mode – Assign Profile, then select Don’t color manage…), the values also stay at 200,100,200, and the file will look like the darker color in an unmanaged app. If you are running Win XP (or Me?), an easy way to open the files in an unmanaged app environment
is to select the file in explorer, right click it, then select preview. This opens it in the Picture & Fax Viewer Applet, and you can size it really small, and drag it over your Photoshop window for side-by-side comparison.

So in a nutshell, what we’ve said so far is that you shouldn’t worry about what Photoshop does internally to display a color correctly. That just happens. What Proofing to your monitor space does is to give you a look-see at what a file might look like in another app that doesn’t use color management, or what it might look like in an app that uses Monitor RGB as it’s working space. I don’t use Image Ready (haven’t loaded it
so I can’t try this), but I’m under the impression that Image Ready uses Monitor RGB as it’s working space.

So that was a discussion of the area where the two color spaces overlap. Now let’s take a quick look at what’s different in that area defined in
the color space triangles sketch as triangle BGG’, i.e. the area OUTSIDE
of the monitor’s color space.

If you think about what this area represents, it’s a portion of the space where you can create a color in Adobe RGB that your monitor can’t display. Let’s check that out by going to the the Color palette and
setting a color of 0,255,0. You should have a bright green in the Foreground color box of both the Tools and Color palettes. Then select one of your files and click inside of it to fill it with the green. Leave the cursor in the file area, and the info palette should show that the Adobe RGB color value is 0,255,0 and the Monitor space value is also 0,255,0. This is basically saying that we have created a green in Adobe
RGB that is too bright for your monitor to display, but the monitor is doing its best by giving the brightest green it can.

Lets now cut back on the Adobe space color a bit and see what happens. Again a reminder that your monitor and mine have almost zero chance of agreeing here, but the effect should be similar. Go back to the Color palette and set a 50,255,50 green. Select the second new file and click the file space to fill it. For my monitor profile, the info palette
shows 50,255,50 for the actual color and still 0,255,0 for the Monitor color.

In other words, we have dulled down the green in Adobe space a little, but it is still brighter than the monitor can display, so the monitor is still maxxing out on green. You can Toggle Proof (Ctrl-Y) for a visual confirmation. If I go much above 50 blue in Adobe space, I start to see blue going up in the proof space, which to me says that I’m moving into
the area where the triangles overlap. You can play with different proof settings here to see if you can rationalize the details of what you see, and compare them with the results from the ‘in gamut’ magenta examples.

So the summary on this BGG’ area is that you can create theoretical colors in Adobe RGB space that your monitor can’t achieve. Whether this represents a problem I can’t say, but probably not a major one, if at
all. Is there a green in nature that’s so bright that it fits into this regieme? If so, can film truly capture it? Can a scanner capture it? A digicam? Can a printer print it? All things to think about.
One final thought. I think you are on the right track in calibrating your monitor. Unless it’s pretty accurate, your chances of implementing
a successful color managed workflow are significantly hampered. Some say it’s hopeless without a ‘perfect’ monitor calibration & profile. I don’t know if it’s that black & white.

My personal experience is that I spent a LOT of time trying to get my monitor in calibration using Adobe gamma. I feel it certainly improved things from before I used it. I also checked it with a myriad of visual aids available on the web, and I was pretty confident that I had it ‘right’.

Then I had the chance to use a colorimeter, and do a ‘professional’ grade calibration & profile. All I can say is WOW. The color of my wallpaper changed noticeably, and the neutral grey background used by Photoshop (and other apps) suddenly really looked grey. I had previously thought it was grey, but as soon as I did the instrument calibration and saw the ‘new’ grey, I realized that it had had a sorta reddish brown cast.

I also found that the 1000 or so film scans that I had done over several months prior to the ‘real’ calibration needed to be redone. Fortunately, it was a ‘constant offset’ situation, so I could do a Photoshop action to add some contrast, remove some brightness, and add some saturation, and batch bang them all out with minimal pain.
The point here is that you are doing the right thing by paying attention
to your monitor. And the best solution is not a freebie, so each person needs to consider his/her circunstances and do the trade-offs. But for what it’s worth, the best technique that you can personally justify will pay dividends.

Best of luck in your efforts to understand color management. Sorry this got so long.

Great article, and full of interesting information for those who take the time to work it through. I’d like to add it, with your permission, to a collection of articles on Digital Photography on my web page.

I would also add a couple of things. First – Photoshop’s info palette is your friend. It will tell you, for example, whether you have a perfect neutral or not (when r, g, and b are equal), and do so more accurately than you can by eye.

Second, is the LabMeter gamut viewer image. This is a free download from from curvemeister that uses Phnotoshop’s preview feature to plot the outline of a gamut in Lab space, which like cieXYZ provides a graphic representation of absolute color.

http://www.curvemeister.com/downloads/index.html

Using LabMeter, you can put up several previews at once and check their shapes at different Lightness values. For example you could look at your display profile and Adobe RGB simultaneously, and see how the shapes change as you change the Lightness.


Mike Russell
www.curvemeister.com
www.geigy.2y.net
MG
m.golner
Dec 14, 2004
howldog wrote:
On Mon, 13 Dec 2004 20:32:31 GMT, "Mike G."
wrote:

My personal experience is that I spent a LOT of time trying to get my monitor in calibration using Adobe gamma. I feel it certainly improved things from before I used it. I also checked it with a myriad of visual aids available on the web, and I was pretty confident that I had it ‘right’.
Then I had the chance to use a colorimeter, and do a ‘professional’ grade calibration & profile. All I can say is WOW. The color of my wallpaper changed noticeably, and the neutral grey background used by Photoshop (and other apps) suddenly really looked grey. I had previously thought it was grey, but as soon as I did the instrument calibration and saw the ‘new’ grey, I realized that it had had a sorta reddish brown cast.

what was the software you used?

been thinking of maybe doing this myself.
howldog,

Will be happy to answer, but did you mean the software and visual aids from the web I referred to in the first paragraph, or the ‘professional’ calibration from the second paragraph, which is really a package of hardware and software? Let me know which.

Thanks,
Mike
MG
m.golner
Dec 14, 2004
howldog wrote:

On Mon, 13 Dec 2004 20:32:31 GMT, "Mike G."
wrote:

My personal experience is that I spent a LOT of time trying to get my monitor in calibration using Adobe gamma. I feel it certainly improved things from before I used it. I also checked it with a myriad of visual aids available on the web, and I was pretty confident that I had it ‘right’.
Then I had the chance to use a colorimeter, and do a ‘professional’ grade calibration & profile. All I can say is WOW. The color of my wallpaper changed noticeably, and the neutral grey background used by Photoshop (and other apps) suddenly really looked grey. I had previously thought it was grey, but as soon as I did the instrument calibration and saw the ‘new’ grey, I realized that it had had a sorta reddish brown cast.

what was the software you used?

been thinking of maybe doing this myself.

howldog,

Will be happy to answer, but did you mean the software and visual aids from the web I referred to in the first paragraph, or the ‘professional’ calibration from the second paragraph, which is really a package of hardware and software? Let me know which.

Thanks,
Mike
MG
m.golner
Dec 14, 2004
Mike,

Thanks for your kind comments. Of course you can link to it. If you want to, you can also excerpt it, edit it for clarity, rehost it, etc. As far as I’m concerned, I put it in the public domain and am more than flattered if someone actually takes the time to read through it. Though not necessary, thanks for asking.

I’m anxious to try some of the downloads on your website. I’m sure I speak for many who appreciate what people like you do for those of us struggling to make sense out of all of this. The free downloads often contain the key piece of information we need. I think your tools are certainly more instructive than drawing a couple of triangles on a piece of paper.

A question on your comment re: the Info pallette. I don’t know how to sample an area that’s not in a file window. Your comment implies that it can be done. How?

Again, thanks for your feedback.

Regards,
Mike

Mike Russell wrote:
Great article, and full of interesting information for those who take the time to work it through. I’d like to add it, with your permission, to a collection of articles on Digital Photography on my web page.
I would also add a couple of things. First – Photoshop’s info palette is your friend. It will tell you, for example, whether you have a perfect neutral or not (when r, g, and b are equal), and do so more accurately than you can by eye.

Second, is the LabMeter gamut viewer image. This is a free download from from curvemeister that uses Phnotoshop’s preview feature to plot the outline of a gamut in Lab space, which like cieXYZ provides a graphic representation of absolute color.

http://www.curvemeister.com/downloads/index.html

Using LabMeter, you can put up several previews at once and check their shapes at different Lightness values. For example you could look at your display profile and Adobe RGB simultaneously, and see how the shapes change as you change the Lightness.
MR
Mike Russell
Dec 14, 2004
Mike G. wrote:
Mike,

Thanks for your kind comments. Of course you can link to it. If you want to, you can also excerpt it, edit it for clarity, rehost it, etc. As far as I’m concerned, I put it in the public domain and am more than flattered if someone actually takes the time to read through it. Though not necessary, thanks for asking.

Thanks. You’re right that there is no legal requirement, but I think it’s an important courtesy to let the author know before putting his or her material on the web. For one thing, this way I’m guaranteed at least one enthusiastic proof reader – or *reader* for that matter, heh. 🙂

I’m anxious to try some of the downloads on your website. I’m sure I speak for many who appreciate what people like you do for those of us struggling to make sense out of all of this. The free downloads often contain the key piece of information we need. I think your tools are certainly more instructive than drawing a couple of triangles on a piece of paper.

I think both are important, and etting the basic principles across clearly and simply is harder to do than most people realize. Your posting did that very well.

A question on your comment re: the Info pallette. I don’t know how to sample an area that’s not in a file window. Your comment implies that it can be done. How?

The info palette only operates within a file window, and certain other areas in Photoshop such as the swatches and color palette. But you can indirectly use the info palette to check the RGB values of any pixel on the screen by first doing a screen capture, then creating a new document in Photoshop and pasting the capture to the window for that document.

I actually happen to be doing this quite a lot at the moment because I’m debugging software that converts color values to the display profile. —

Mike Russell
www.curvemeister.com
www.geigy.2y.net
H
howldog
Dec 14, 2004
On Tue, 14 Dec 2004 01:12:02 GMT, "Mike G."
wrote:

howldog wrote:
On Mon, 13 Dec 2004 20:32:31 GMT, "Mike G."
wrote:

My personal experience is that I spent a LOT of time trying to get my monitor in calibration using Adobe gamma. I feel it certainly improved things from before I used it. I also checked it with a myriad of visual aids available on the web, and I was pretty confident that I had it ‘right’.
Then I had the chance to use a colorimeter, and do a ‘professional’ grade calibration & profile. All I can say is WOW. The color of my wallpaper changed noticeably, and the neutral grey background used by Photoshop (and other apps) suddenly really looked grey. I had previously thought it was grey, but as soon as I did the instrument calibration and saw the ‘new’ grey, I realized that it had had a sorta reddish brown cast.

what was the software you used?

been thinking of maybe doing this myself.
howldog,

Will be happy to answer, but did you mean the software and visual aids from the web I referred to in the first paragraph, or the ‘professional’ calibration from the second paragraph, which is really a package of hardware and software? Let me know which.

second paragraph. was under the impression you bought some hardware and software.
MG
m.golner
Dec 14, 2004
howldog wrote:
On Tue, 14 Dec 2004 01:12:02 GMT, "Mike G."
wrote:

howldog wrote:

On Mon, 13 Dec 2004 20:32:31 GMT, "Mike G."
wrote:

My personal experience is that I spent a LOT of time trying to get my monitor in calibration using Adobe gamma. I feel it certainly improved things from before I used it. I also checked it with a myriad of visual aids available on the web, and I was pretty confident that I had it ‘right’.
Then I had the chance to use a colorimeter, and do a ‘professional’ grade calibration & profile. All I can say is WOW. The color of my wallpaper changed noticeably, and the neutral grey background used by Photoshop (and other apps) suddenly really looked grey. I had previously thought it was grey, but as soon as I did the instrument calibration and saw the ‘new’ grey, I realized that it had had a sorta reddish brown cast.

what was the software you used?

been thinking of maybe doing this myself.

howldog,

Will be happy to answer, but did you mean the software and visual aids

from the web I referred to in the first paragraph, or the ‘professional’

calibration from the second paragraph, which is really a package of hardware and software? Let me know which.

second paragraph. was under the impression you bought some hardware and software.
OK, thanks for the clarification.

I bought a system made by Gretag-Macbeth called the Eye-One Display2, which came with Match 3.0 software. FWIW, I bought it from a reseller in Seattle called Chromix (www.chromix.com, the ColorGear section of the website).

I think there are also highly regarded systems available from Monaco Systems. And there are other manufacturers, some of whom have received endorsements from some news posts, while getting flamed by other posts. Here are a couple of links to some reviews. Note that for the first link, the evaluation was done just before the Display2 was released by GMB, and GMB claims the new one is better (which shocks me, of course).

http://www.shootsmarter.com/infocenter/wc026a.htm
http://www.drycreekphoto.com/Learn/monitor_calibration_tools .htm

The second link has tests for both the new and old GMB models, and actually seems to verify GMB’s claims.

Anyway, you should read these articles and make your choice based on the parameters that are important to you. Fortunately, there seem to be several good choices available.

Hope this helps.

Mike
H
howldog
Dec 14, 2004
On Tue, 14 Dec 2004 18:27:24 GMT, "Mike G."
wrote:

howldog wrote:
On Tue, 14 Dec 2004 01:12:02 GMT, "Mike G."
wrote:

howldog wrote:

On Mon, 13 Dec 2004 20:32:31 GMT, "Mike G."
wrote:

My personal experience is that I spent a LOT of time trying to get my monitor in calibration using Adobe gamma. I feel it certainly improved things from before I used it. I also checked it with a myriad of visual aids available on the web, and I was pretty confident that I had it ‘right’.
Then I had the chance to use a colorimeter, and do a ‘professional’ grade calibration & profile. All I can say is WOW. The color of my wallpaper changed noticeably, and the neutral grey background used by Photoshop (and other apps) suddenly really looked grey. I had previously thought it was grey, but as soon as I did the instrument calibration and saw the ‘new’ grey, I realized that it had had a sorta reddish brown cast.

what was the software you used?

been thinking of maybe doing this myself.

howldog,

Will be happy to answer, but did you mean the software and visual aids

from the web I referred to in the first paragraph, or the ‘professional’

calibration from the second paragraph, which is really a package of hardware and software? Let me know which.

second paragraph. was under the impression you bought some hardware and software.
OK, thanks for the clarification.

I bought a system made by Gretag-Macbeth called the Eye-One Display2, which came with Match 3.0 software. FWIW, I bought it from a reseller in Seattle called Chromix (www.chromix.com, the ColorGear section of the website).

I think there are also highly regarded systems available from Monaco

i’ve looked at both and i dont think i wanna layout the cash for the Gretag. the Monaco, i might. thanks for your info.

Systems. And there are other manufacturers, some of whom have received endorsements from some news posts, while getting flamed by other posts. Here are a couple of links to some reviews. Note that for the first link, the evaluation was done just before the Display2 was released by GMB, and GMB claims the new one is better (which shocks me, of course).
http://www.shootsmarter.com/infocenter/wc026a.htm
http://www.drycreekphoto.com/Learn/monitor_calibration_tools .htm
The second link has tests for both the new and old GMB models, and actually seems to verify GMB’s claims.

Anyway, you should read these articles and make your choice based on the parameters that are important to you. Fortunately, there seem to be several good choices available.

Hope this helps.

Mike
MG
m.golner
Dec 14, 2004
Mike Russell wrote:
Mike G. wrote:

A question on your comment re: the Info pallette. I don’t know how to sample an area that’s not in a file window. Your comment implies that it can be done. How?

The info palette only operates within a file window, and certain other areas in Photoshop such as the swatches and color palette. But you can indirectly use the info palette to check the RGB values of any pixel on the screen by first doing a screen capture, then creating a new document in Photoshop and pasting the capture to the window for that document.

I actually happen to be doing this quite a lot at the moment because I’m debugging software that converts color values to the display profile.

Mike,

I tried your technique and it works well. Thanks.

Then, talk about coincidences, I recently started reading Real World Photoshop 7, and this morning got to page 42, where they talk about this very thing.

They suggest a different trick, which is to click the eyedropper tool within a file window, but hold the button down, and then drag the dropper to any point on the screen, whether wallpaper, PS background, another app, whatever. Then release the button and you will have put that color into the foreground color box in both the Info and Color palettes. You can hover over either of them, and the color data is shown in your Info pallette.

Thought I’d pass this on to you.
MG
m.golner
Dec 14, 2004
Mike Russell wrote:
Mike G. wrote:

A question on your comment re: the Info pallette. I don’t know how to sample an area that’s not in a file window. Your comment implies that it can be done. How?

The info palette only operates within a file window, and certain other areas in Photoshop such as the swatches and color palette. But you can indirectly use the info palette to check the RGB values of any pixel on the screen by first doing a screen capture, then creating a new document in Photoshop and pasting the capture to the window for that document.

I actually happen to be doing this quite a lot at the moment because I’m debugging software that converts color values to the display profile.

Mike,

I tried your technique and it works well. Thanks.

Then, talk about coincidences, I recently started reading Real World Photoshop 7, and this morning got to page 42, where they talk about this very thing.

They suggest a different trick, which is to click the eyedropper tool within a file window, but hold the button down, and then drag the dropper to any point on the screen, whether wallpaper, PS background, another app, whatever. Then release the button and you will have put that color into the foreground color box in both the Tools and Color palettes. You can hover over either of them, and the color data is shown in your Info pallette.

Thought I’d pass this on to you.
MR
Mike Russell
Dec 14, 2004
Mike G. wrote:
….
Then, talk about coincidences, I recently started reading Real World Photoshop 7, and this morning got to page 42, where they talk about this
very thing.

They suggest a different trick, which is to click the eyedropper tool within a file window, but hold the button down, and then drag the dropper
to any point on the screen, whether wallpaper, PS background, another app, whatever. Then release the button and you will have put that color
into the foreground color box in both the Tools and Color palettes. You
can hover over either of them, and the color data is shown in your Info pallette.

Thought I’d pass this on to you.

Spiffo – works nicely, and will save me some time with what I’m doing now. —

Mike Russell
www.curvemeister.com
www.geigy.2y.net
X
xerj
Dec 17, 2004
WOW Mike.

Thanks for going to all that effort.

I’m working through your post, and I can’t say I fully understand it yet, but things are definitely starting to fall into place.

It’s a hell of a topic.

Thanks again!

"Mike G." wrote in message
The question makes sense, I’m not sure that this answer will, however. I’ve wondered about this for a couple of years, and over the past several months have put a lot of effort into understanding what’s going on. I either understand it better (but not completely) now, or am simply more delusional, but here’s an attempt to explain it.
Before we get into the nitty grits, we need to do a couple of things. The first is a freehand sketch to show the relationship between the color spaces involved, namely Adobe RGB 1998, and Monitor RGB. Adobe RGB is of course fixed, and Monitor RGB depends on your particular monitor and its calibration, but the idea should still be valid.
First, draw a triangle with each side about equal in length, and rotated so the base is about 30 degrees counterclockwise from horizontal, i.e. lower right corner tipped up. Label the lower left corner as B, the right corner as R, and the top corner as G. Triangle RGB represents Adobe RGB space in CIE Yxy coordinates, one of several common ways to look at color spaces. Now, starting at G, go along line GR about 25% of the way toward R and put another point. Label this point G’. Triangle RG’B represents a typical monitor color space. Note that this is only a very rough representation, but it will help in understanding some of the things that happen. This is a two dimensional representation of a three dimensional phenomenon, so it holds true enough to show a concept, but breaks down if you try to use it too precisely.

The next thing is simply a configuration setting in Photoshop. I don’t know what version you are using, but this is based on PS7. In the menu bar, go to Window, and place a check by Info. Then in the Info Palette, click the little triangle at the top right and select Palette Options, where you should set First Color Readout to Actual Color, and Second Color Readout to Proof Color. This will let you see both the RGB value from the file, and if you have selected Monitor RGB as the proof space, the RGB value that is actually being sent to your monitor, for any point in a file your cursor hovers over. It can be really enlightening.
Next, again in Photoshop, again in the Window menu, place a check by Color. In the color palette, make sure the foreground (upper left overlapping square) is selected (double line outline). In the Tool Palette, select the Paint Bucket tool (make sure Tools is also checked in the Window menu).

Finally, open 2 new files, Contents set to White. They should be small, like 300×300 pixels. We’re just going to fill them each with a single color. I assume that you have Adobe RGB set as your default working space, so the files should end up created and tagged as Adobe RGB color space.

As we start going through things, there are two ideas to keep in mind.
The first is that as you look at the two color space triangles, you notice that there is a large area where they overlap, and another smaller area OUTSIDE of Monitor color space but WITHIN Adobe RGB. Behavior is different in each of these two areas. Let’s just set that thought aside for the time being.

Second is that in Photoshop there are different ways to set up the Monitor Proof space, and how you do it will determine the effect you get. Briefly, the first way is by selecting View – Proof Setup, then scrolling down to Monitor RGB. The second is by selecting View – Proof Setup – Custom. Then in the Proof Setup dialog box, you open the Profile dropdown list and select your monitor’s profile. This is (or should be) the same profile that Photoshop uses by the first method, BUT, you also get control over whether to Preserve Color Numbers, and if you choose not to, you get control over rendering intent. By comparison, when you use the first method, Photoshop (I’m 99% sure) locks you in to Preserve Color Number mode.

The difference here is that the first method simply passes the color numbers through from one color space to another, while the second method attempts to convert the color numbers so that the color looks the same as you move from one space to the other.

For now, select each of your new files in turn and set the proof space to Monitor RGB using the second method. Uncheck Preserve Color Numbers and select the Intent of your choice. I like Relative Colorimetric Intent w/ Black Point compensation as a starting point.

We’ll start by looking at a point that lies comfortably within both the Adobe RGB and the Monitor RGB color spaces. Let’s work with Adobe RGB 200,100,200, which I would call a mid-tone magenta. Go to the Color palette and enter the color numbers R: 200, G: 100, B: 200. You should have a magenta in the Foreground color box of both the Tools and Color palettes. Then click the title bar of one of the new files you created, to select it, then click in the white space, and the paint bucket should fill the file with that color. Leave the cursor in the file area, and the Info palette should show that the Adobe RGB color value is 200,100,200 (left side) and the Monitor RGB space value (for MY monitor) is 227,97,202 (right side). Your value is most certainly bound to be different than mine. The important thing is that the Monitor space color number is different than the Adobe space color number in order to give the same appearance. If you toggle Proof Colors on and off (Ctrl-Y) you should see no change in color. (As an aside, maybe this is the check on the quality of your monitor profile you referred to in your reply to Waldo. If you have a poor profile, you might see a visual change here.)
By way of contrast, select the second of your new files and dump the same 200,100,200 color into it. Next, set proofing for this file to Preserve Color Numbers. Now you will see in the Info palette that both Adobe RGB and Monitor RGB values are 200,100,200, and as you toggle from Adobe RGB space to Monitor RGB space, you will see the color change, to a more blue appearing hue (actually more cyan, I think). Again, depending on your monitor’s profile, you may get different results.
Let’s try to rationalize this with what we see on the two color space triangles we drew earlier. First it’s important to understand that we have drawn these two color spaces imposed on a CIE Yxy coordinate system, and that we should consider the CIE space to be absolute. It is a device independent space, and each point on the paper is IN ACTUALITY a DIFFERENT, UNIQUE color. Hence, G and G’ are different colors, for example, even though they are both 0,255,0 in their own space. Forget about how our devices render the numbers. Different points on this plot are different colors, period.

Now let’s look at our 200,100,200 magenta. If we consider it’s location in the Adobe RGB space, i.e. triangle RGB, it will fall about midway between R and B, then about 20% of the way up toward G. By comparison, in the Monitor RGB space, i.e. RG’B, it will likewise fall about midway between R and B, but then about 20% of the way up toward G’. These are clearly two different points on the paper, so we have the color shift if we Preserve the Color Numbers. However, if we let the Adobe Color Engine do it’s color management thing, it will convert the 200,100,200 magenta in Adobe space to 227,97,202 (my monitor) to give the same appearing color.

At this point in time it may be worth considering that all of this is done ‘on the fly’, as it relates to the monitor’s displaying of colors. Adobe doesn’t change file color numbers to effect an accurate display rendering. The scenarios we have just considered are all done ‘in the back room’. We can think of it as the Actual color number is what’s in the file, and the Proof color number is what’s being faked to the monitor to get it to look right.

Here’s another way to look at this, and it might be a bit more tied to something we can physically imagine. If you were to take the file with the 200,100,200 magenta in it (tagged with Adobe RGB space), and CONVERT the profile to Monitor RGB (Image – Mode – Convert to Profile, then select your Monitor profile, and select relative colorimetric, bpc, etc), then save it, then open it in another application that doesn’t have color management, it should look like the the actual 200,100,200 color in Photoshop. Note that the colors will have been changed in the file to color number 227,97,202 (again, my monitor). If however, you ASSIGN the profile to Monitor RGB (Image – Mode – Assign Profile, then select Monitor profile), the color values in the file stay as 200,100,200, but the file is tagged with Monitor RGB as the profile. If you open this file in a color unmanaged app, the file will appear as the darker, more cyan version of magenta. Likewise, if you STRIP the profile (Image – Mode – Assign Profile, then select Don’t color manage…), the values also stay at 200,100,200, and the file will look like the darker color in an unmanaged app. If you are running Win XP (or Me?), an easy way to open the files in an unmanaged app environment is to select the file in explorer, right click it, then select preview. This opens it in the Picture & Fax Viewer Applet, and you can size it really small, and drag it over your Photoshop window for side-by-side comparison.
So in a nutshell, what we’ve said so far is that you shouldn’t worry about what Photoshop does internally to display a color correctly. That just happens. What Proofing to your monitor space does is to give you a look-see at what a file might look like in another app that doesn’t use color management, or what it might look like in an app that uses Monitor RGB as it’s working space. I don’t use Image Ready (haven’t loaded it so I can’t try this), but I’m under the impression that Image Ready uses Monitor RGB as it’s working space.

So that was a discussion of the area where the two color spaces overlap. Now let’s take a quick look at what’s different in that area defined in the color space triangles sketch as triangle BGG’, i.e. the area OUTSIDE of the monitor’s color space.

If you think about what this area represents, it’s a portion of the space where you can create a color in Adobe RGB that your monitor can’t display. Let’s check that out by going to the the Color palette and setting a color of 0,255,0. You should have a bright green in the Foreground color box of both the Tools and Color palettes. Then select one of your files and click inside of it to fill it with the green. Leave the cursor in the file area, and the info palette should show that the Adobe RGB color value is 0,255,0 and the Monitor space value is also 0,255,0. This is basically saying that we have created a green in Adobe RGB that is too bright for your monitor to display, but the monitor is doing its best by giving the brightest green it can.

Lets now cut back on the Adobe space color a bit and see what happens. Again a reminder that your monitor and mine have almost zero chance of agreeing here, but the effect should be similar. Go back to the Color palette and set a 50,255,50 green. Select the second new file and click the file space to fill it. For my monitor profile, the info palette shows 50,255,50 for the actual color and still 0,255,0 for the Monitor color.
In other words, we have dulled down the green in Adobe space a little, but it is still brighter than the monitor can display, so the monitor is still maxxing out on green. You can Toggle Proof (Ctrl-Y) for a visual confirmation. If I go much above 50 blue in Adobe space, I start to see blue going up in the proof space, which to me says that I’m moving into the area where the triangles overlap. You can play with different proof settings here to see if you can rationalize the details of what you see, and compare them with the results from the ‘in gamut’ magenta examples.
So the summary on this BGG’ area is that you can create theoretical colors in Adobe RGB space that your monitor can’t achieve. Whether this represents a problem I can’t say, but probably not a major one, if at all. Is there a green in nature that’s so bright that it fits into this regieme? If so, can film truly capture it? Can a scanner capture it? A digicam? Can a printer print it? All things to think about.
One final thought. I think you are on the right track in calibrating your monitor. Unless it’s pretty accurate, your chances of implementing a successful color managed workflow are significantly hampered. Some say it’s hopeless without a ‘perfect’ monitor calibration & profile. I don’t know if it’s that black & white.

My personal experience is that I spent a LOT of time trying to get my monitor in calibration using Adobe gamma. I feel it certainly improved things from before I used it. I also checked it with a myriad of visual aids available on the web, and I was pretty confident that I had it ‘right’.

Then I had the chance to use a colorimeter, and do a ‘professional’ grade calibration & profile. All I can say is WOW. The color of my wallpaper changed noticeably, and the neutral grey background used by Photoshop (and other apps) suddenly really looked grey. I had previously thought it was grey, but as soon as I did the instrument calibration and saw the ‘new’ grey, I realized that it had had a sorta reddish brown cast.
I also found that the 1000 or so film scans that I had done over several months prior to the ‘real’ calibration needed to be redone. Fortunately, it was a ‘constant offset’ situation, so I could do a Photoshop action to add some contrast, remove some brightness, and add some saturation, and batch bang them all out with minimal pain.

The point here is that you are doing the right thing by paying attention to your monitor. And the best solution is not a freebie, so each person needs to consider his/her circunstances and do the trade-offs. But for what it’s worth, the best technique that you can personally justify will pay dividends.

Best of luck in your efforts to understand color management. Sorry this got so long.

xerj wrote:
There are so many questions, but I’ll start with the first:-
I’ve profiled my monitor using Adobe Gamma. When I select Proof Colors with Monitor selected, the results look pretty muddy and horrible. What exactly is this telling me? Shouldn’t it not change as
the monitor profile is what is used as an output at all times anyway (Adobe 1998 RGB is the working space, although some embedded profiles are sRGB)?

Sorry if the question doesn’t make sense.
X
xerj
Dec 17, 2004
Follow up:

Done some more work with your tutorial, and it really is all starting to fall into place.

You’ve succesfully demystified what was a very substantial block in understanding the beast called Color Management.

Hopefully the info will help others.

"Mike G." wrote in message
The question makes sense, I’m not sure that this answer will, however. I’ve wondered about this for a couple of years, and over the past several months have put a lot of effort into understanding what’s going on. I either understand it better (but not completely) now, or am simply more delusional, but here’s an attempt to explain it.
Before we get into the nitty grits, we need to do a couple of things. The first is a freehand sketch to show the relationship between the color spaces involved, namely Adobe RGB 1998, and Monitor RGB. Adobe RGB is of course fixed, and Monitor RGB depends on your particular monitor and its calibration, but the idea should still be valid.
First, draw a triangle with each side about equal in length, and rotated so the base is about 30 degrees counterclockwise from horizontal, i.e. lower right corner tipped up. Label the lower left corner as B, the right corner as R, and the top corner as G. Triangle RGB represents Adobe RGB space in CIE Yxy coordinates, one of several common ways to look at color spaces. Now, starting at G, go along line GR about 25% of the way toward R and put another point. Label this point G’. Triangle RG’B represents a typical monitor color space. Note that this is only a very rough representation, but it will help in understanding some of the things that happen. This is a two dimensional representation of a three dimensional phenomenon, so it holds true enough to show a concept, but breaks down if you try to use it too precisely.

The next thing is simply a configuration setting in Photoshop. I don’t know what version you are using, but this is based on PS7. In the menu bar, go to Window, and place a check by Info. Then in the Info Palette, click the little triangle at the top right and select Palette Options, where you should set First Color Readout to Actual Color, and Second Color Readout to Proof Color. This will let you see both the RGB value from the file, and if you have selected Monitor RGB as the proof space, the RGB value that is actually being sent to your monitor, for any point in a file your cursor hovers over. It can be really enlightening.
Next, again in Photoshop, again in the Window menu, place a check by Color. In the color palette, make sure the foreground (upper left overlapping square) is selected (double line outline). In the Tool Palette, select the Paint Bucket tool (make sure Tools is also checked in the Window menu).

Finally, open 2 new files, Contents set to White. They should be small, like 300×300 pixels. We’re just going to fill them each with a single color. I assume that you have Adobe RGB set as your default working space, so the files should end up created and tagged as Adobe RGB color space.

As we start going through things, there are two ideas to keep in mind.
The first is that as you look at the two color space triangles, you notice that there is a large area where they overlap, and another smaller area OUTSIDE of Monitor color space but WITHIN Adobe RGB. Behavior is different in each of these two areas. Let’s just set that thought aside for the time being.

Second is that in Photoshop there are different ways to set up the Monitor Proof space, and how you do it will determine the effect you get. Briefly, the first way is by selecting View – Proof Setup, then scrolling down to Monitor RGB. The second is by selecting View – Proof Setup – Custom. Then in the Proof Setup dialog box, you open the Profile dropdown list and select your monitor’s profile. This is (or should be) the same profile that Photoshop uses by the first method, BUT, you also get control over whether to Preserve Color Numbers, and if you choose not to, you get control over rendering intent. By comparison, when you use the first method, Photoshop (I’m 99% sure) locks you in to Preserve Color Number mode.

The difference here is that the first method simply passes the color numbers through from one color space to another, while the second method attempts to convert the color numbers so that the color looks the same as you move from one space to the other.

For now, select each of your new files in turn and set the proof space to Monitor RGB using the second method. Uncheck Preserve Color Numbers and select the Intent of your choice. I like Relative Colorimetric Intent w/ Black Point compensation as a starting point.

We’ll start by looking at a point that lies comfortably within both the Adobe RGB and the Monitor RGB color spaces. Let’s work with Adobe RGB 200,100,200, which I would call a mid-tone magenta. Go to the Color palette and enter the color numbers R: 200, G: 100, B: 200. You should have a magenta in the Foreground color box of both the Tools and Color palettes. Then click the title bar of one of the new files you created, to select it, then click in the white space, and the paint bucket should fill the file with that color. Leave the cursor in the file area, and the Info palette should show that the Adobe RGB color value is 200,100,200 (left side) and the Monitor RGB space value (for MY monitor) is 227,97,202 (right side). Your value is most certainly bound to be different than mine. The important thing is that the Monitor space color number is different than the Adobe space color number in order to give the same appearance. If you toggle Proof Colors on and off (Ctrl-Y) you should see no change in color. (As an aside, maybe this is the check on the quality of your monitor profile you referred to in your reply to Waldo. If you have a poor profile, you might see a visual change here.)
By way of contrast, select the second of your new files and dump the same 200,100,200 color into it. Next, set proofing for this file to Preserve Color Numbers. Now you will see in the Info palette that both Adobe RGB and Monitor RGB values are 200,100,200, and as you toggle from Adobe RGB space to Monitor RGB space, you will see the color change, to a more blue appearing hue (actually more cyan, I think). Again, depending on your monitor’s profile, you may get different results.
Let’s try to rationalize this with what we see on the two color space triangles we drew earlier. First it’s important to understand that we have drawn these two color spaces imposed on a CIE Yxy coordinate system, and that we should consider the CIE space to be absolute. It is a device independent space, and each point on the paper is IN ACTUALITY a DIFFERENT, UNIQUE color. Hence, G and G’ are different colors, for example, even though they are both 0,255,0 in their own space. Forget about how our devices render the numbers. Different points on this plot are different colors, period.

Now let’s look at our 200,100,200 magenta. If we consider it’s location in the Adobe RGB space, i.e. triangle RGB, it will fall about midway between R and B, then about 20% of the way up toward G. By comparison, in the Monitor RGB space, i.e. RG’B, it will likewise fall about midway between R and B, but then about 20% of the way up toward G’. These are clearly two different points on the paper, so we have the color shift if we Preserve the Color Numbers. However, if we let the Adobe Color Engine do it’s color management thing, it will convert the 200,100,200 magenta in Adobe space to 227,97,202 (my monitor) to give the same appearing color.

At this point in time it may be worth considering that all of this is done ‘on the fly’, as it relates to the monitor’s displaying of colors. Adobe doesn’t change file color numbers to effect an accurate display rendering. The scenarios we have just considered are all done ‘in the back room’. We can think of it as the Actual color number is what’s in the file, and the Proof color number is what’s being faked to the monitor to get it to look right.

Here’s another way to look at this, and it might be a bit more tied to something we can physically imagine. If you were to take the file with the 200,100,200 magenta in it (tagged with Adobe RGB space), and CONVERT the profile to Monitor RGB (Image – Mode – Convert to Profile, then select your Monitor profile, and select relative colorimetric, bpc, etc), then save it, then open it in another application that doesn’t have color management, it should look like the the actual 200,100,200 color in Photoshop. Note that the colors will have been changed in the file to color number 227,97,202 (again, my monitor). If however, you ASSIGN the profile to Monitor RGB (Image – Mode – Assign Profile, then select Monitor profile), the color values in the file stay as 200,100,200, but the file is tagged with Monitor RGB as the profile. If you open this file in a color unmanaged app, the file will appear as the darker, more cyan version of magenta. Likewise, if you STRIP the profile (Image – Mode – Assign Profile, then select Don’t color manage…), the values also stay at 200,100,200, and the file will look like the darker color in an unmanaged app. If you are running Win XP (or Me?), an easy way to open the files in an unmanaged app environment is to select the file in explorer, right click it, then select preview. This opens it in the Picture & Fax Viewer Applet, and you can size it really small, and drag it over your Photoshop window for side-by-side comparison.
So in a nutshell, what we’ve said so far is that you shouldn’t worry about what Photoshop does internally to display a color correctly. That just happens. What Proofing to your monitor space does is to give you a look-see at what a file might look like in another app that doesn’t use color management, or what it might look like in an app that uses Monitor RGB as it’s working space. I don’t use Image Ready (haven’t loaded it so I can’t try this), but I’m under the impression that Image Ready uses Monitor RGB as it’s working space.

So that was a discussion of the area where the two color spaces overlap. Now let’s take a quick look at what’s different in that area defined in the color space triangles sketch as triangle BGG’, i.e. the area OUTSIDE of the monitor’s color space.

If you think about what this area represents, it’s a portion of the space where you can create a color in Adobe RGB that your monitor can’t display. Let’s check that out by going to the the Color palette and setting a color of 0,255,0. You should have a bright green in the Foreground color box of both the Tools and Color palettes. Then select one of your files and click inside of it to fill it with the green. Leave the cursor in the file area, and the info palette should show that the Adobe RGB color value is 0,255,0 and the Monitor space value is also 0,255,0. This is basically saying that we have created a green in Adobe RGB that is too bright for your monitor to display, but the monitor is doing its best by giving the brightest green it can.

Lets now cut back on the Adobe space color a bit and see what happens. Again a reminder that your monitor and mine have almost zero chance of agreeing here, but the effect should be similar. Go back to the Color palette and set a 50,255,50 green. Select the second new file and click the file space to fill it. For my monitor profile, the info palette shows 50,255,50 for the actual color and still 0,255,0 for the Monitor color.
In other words, we have dulled down the green in Adobe space a little, but it is still brighter than the monitor can display, so the monitor is still maxxing out on green. You can Toggle Proof (Ctrl-Y) for a visual confirmation. If I go much above 50 blue in Adobe space, I start to see blue going up in the proof space, which to me says that I’m moving into the area where the triangles overlap. You can play with different proof settings here to see if you can rationalize the details of what you see, and compare them with the results from the ‘in gamut’ magenta examples.
So the summary on this BGG’ area is that you can create theoretical colors in Adobe RGB space that your monitor can’t achieve. Whether this represents a problem I can’t say, but probably not a major one, if at all. Is there a green in nature that’s so bright that it fits into this regieme? If so, can film truly capture it? Can a scanner capture it? A digicam? Can a printer print it? All things to think about.
One final thought. I think you are on the right track in calibrating your monitor. Unless it’s pretty accurate, your chances of implementing a successful color managed workflow are significantly hampered. Some say it’s hopeless without a ‘perfect’ monitor calibration & profile. I don’t know if it’s that black & white.

My personal experience is that I spent a LOT of time trying to get my monitor in calibration using Adobe gamma. I feel it certainly improved things from before I used it. I also checked it with a myriad of visual aids available on the web, and I was pretty confident that I had it ‘right’.

Then I had the chance to use a colorimeter, and do a ‘professional’ grade calibration & profile. All I can say is WOW. The color of my wallpaper changed noticeably, and the neutral grey background used by Photoshop (and other apps) suddenly really looked grey. I had previously thought it was grey, but as soon as I did the instrument calibration and saw the ‘new’ grey, I realized that it had had a sorta reddish brown cast.
I also found that the 1000 or so film scans that I had done over several months prior to the ‘real’ calibration needed to be redone. Fortunately, it was a ‘constant offset’ situation, so I could do a Photoshop action to add some contrast, remove some brightness, and add some saturation, and batch bang them all out with minimal pain.

The point here is that you are doing the right thing by paying attention to your monitor. And the best solution is not a freebie, so each person needs to consider his/her circunstances and do the trade-offs. But for what it’s worth, the best technique that you can personally justify will pay dividends.

Best of luck in your efforts to understand color management. Sorry this got so long.

xerj wrote:
There are so many questions, but I’ll start with the first:-
I’ve profiled my monitor using Adobe Gamma. When I select Proof Colors with Monitor selected, the results look pretty muddy and horrible. What exactly is this telling me? Shouldn’t it not change as
the monitor profile is what is used as an output at all times anyway (Adobe 1998 RGB is the working space, although some embedded profiles are sRGB)?

Sorry if the question doesn’t make sense.
MG
m.golner
Dec 18, 2004
xerj wrote:
Follow up:

Done some more work with your tutorial, and it really is all starting to fall into place.

You’ve succesfully demystified what was a very substantial block in understanding the beast called Color Management.

Hopefully the info will help others.

Glad it helped. It actually helped me a quite a bit, too. Writing down what I thought I was starting to understand showed me a few points I had sleazed over in my mind, and when I tried to write about those areas and started babbling, it was obvious I needed to dig a little deeper.

I recently finished reading ‘Real World Color Management’, second edition, by Fraser, Murphy, and Bunting, published by Peachpit Press. I can hardily recommend it if you’re up to having your mind boggled for a while. Then after a period of befuddlement, it starts to fall into place. A warning: You will end up wanting a bunch of toys.

Anyway, glad you’re making progress. Yes, it is a beast.
X
xerj
Dec 18, 2004
I’ve seen that book mentioned too many times to resist it any longer. I’ll hunt it out in the New Year.

As for toys, I know I’m going to want a Macbeth. I’ve done the Gamma thing a million times, and I’m pretty sure I’m not at neutral. It’s enough to keep me up at nights. Pathetic, but true.

"Mike G." wrote in message
xerj wrote:
Follow up:

Done some more work with your tutorial, and it really is all starting to fall into place.

You’ve succesfully demystified what was a very substantial block in understanding the beast called Color Management.

Hopefully the info will help others.

Glad it helped. It actually helped me a quite a bit, too. Writing down what I thought I was starting to understand showed me a few points I had sleazed over in my mind, and when I tried to write about those areas and started babbling, it was obvious I needed to dig a little deeper.
I recently finished reading ‘Real World Color Management’, second edition, by Fraser, Murphy, and Bunting, published by Peachpit Press. I can hardily recommend it if you’re up to having your mind boggled for a while. Then after a period of befuddlement, it starts to fall into place. A warning: You will end up wanting a bunch of toys.

Anyway, glad you’re making progress. Yes, it is a beast.

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