White balance

Gordon Pembury wrote:

When I shoot RAW I can adjust white balance after I have taken the shot.
Is there an equivalent way of doing that for a JPEG? E.g. by a curves levels or hue/sat type of adjustment. (I know I can adjust the WB in camera before I take the shot, it’s after I’m interested in )

Any help gratefully received

Gordon

Yes, of course. It’s called color adjusting; one of the basic functions of Photoshop. There are many ways of doing that in Photoshop. Pick up a beginning book on Photoshop or do some hunting on the Web.

Clyde

In article ,
"Gordon Pembury" wrote:

Is there an equivalent way of doing that for a JPEG? E.g. by a curves levels or hue/sat type of adjustment. (I know I can adjust the WB in camera before I take the shot, it’s after I’m interested in )

Yes. Color correction is one of the most basic things people use Photoshop for.

The best tool I’ve found for removing an unwanted color cast is the Curves command.

—
Art, photography, shareware, polyamory, literature, kink: all at http://www.xeromag.com/franklin.html

Thank you for a smart arse rersponse!

I know a fair bit about colour adjustment, thanks. The question is, is there a simple way akin to adjustiung whaite balance in RAW for non RAW pictures

"Clyde" wrote in message

Gordon Pembury wrote:

When I shoot RAW I can adjust white balance after I have taken the shot.
Is there an equivalent way of doing that for a JPEG? E.g. by a curves levels or hue/sat type of adjustment. (I know I can adjust the WB in camera before I take the shot, it’s after I’m interested in )
Any help gratefully received

Gordon

Yes, of course. It’s called color adjusting; one of the basic functions of Photoshop. There are many ways of doing that in Photoshop. Pick up a beginning book on Photoshop or do some hunting on the Web.
Clyde

tacit wrote:

In article ,
"Gordon Pembury" wrote:

Is there an equivalent way of doing that for a JPEG? E.g. by a curves levels or hue/sat type of adjustment. (I know I can adjust the WB in camera before I take the shot, it’s after I’m interested in )

Yes. Color correction is one of the most basic things people use Photoshop for.

The best tool I’ve found for removing an unwanted color cast is the Curves command.

While quite true, my conclusions are that with RAW, it’s simple, clean and leaves no bitter after taste…. with JPEGs, large adjustments seem to leave the image in a poorer state. Sorry I don’t have the words now to be more precise, but is this the experience of others ,and what are the names of such degradation commonly given?

—
John McWilliams

On Mon, 7 Nov 2005 12:37:10 -0000, "Gordon Pembury" wrote:

When I shoot RAW I can adjust white balance after I have taken the shot.
Is there an equivalent way of doing that for a JPEG? E.g. by a curves levels or hue/sat type of adjustment. (I know I can adjust the WB in camera before I take the shot, it’s after I’m interested in )

Any help gratefully received

Gordon

Hi Gordon, don’t cross post. That sets the people (even myself) against you.
Not making excuses for the idiotic responses you received, (they probably don’t even know what cross posting are) but simply stating a act.

Ctrl/L for Levels and open the info palette to search
for a neutral color in order to do your WB.

Dave

In article , Gordon Pembury wrote:

The question is, is
there a simple way akin to adjustiung whaite balance in RAW for non RAW pictures

Picasa2 has, and it’s free.

Roger (whose arse is of an average IQ)

On Mon, 7 Nov 2005 12:37:10 -0000, "Gordon Pembury" wrote:

When I shoot RAW I can adjust white balance after I have taken the shot.
Is there an equivalent way of doing that for a JPEG? E.g. by a curves levels or hue/sat type of adjustment. (I know I can adjust the WB in camera before I take the shot, it’s after I’m interested in )

Any help gratefully received

Gordon

Hi Gordon, don’t cross post. That sets the people (even myself) against you.
Not making excuses for the idiotic responses you received, (they probably don’t even know what cross posting are) but simply stating a fact.

Ctrl/L for Levels and open the info palette to search
for a neutral color in order to do your WB.

Dave

"Gordon Pembury" wrote in message

When I shoot RAW I can adjust white balance after I have taken the shot.
Is there an equivalent way of doing that for a JPEG? E.g. by a curves levels or hue/sat type of adjustment. (I know I can adjust the WB in camera before I take the shot, it’s after I’m interested in )
Any help gratefully received

Gordon

try making a levels adjustment layer
use the white eyedropper to sample the area you want to be the corrected white
there are some other options in the palette too
We made some photos with colored gels and if you hit AUTO it tries to "correct" them to "normal"

On Mon, 07 Nov 2005 10:37:45 -0800, John McWilliams wrote:

The best tool I’ve found for removing an unwanted color cast is the Curves command.

While quite true, my conclusions are that with RAW, it’s simple, clean and leaves no bitter after taste…. with JPEGs, large adjustments seem to leave the image in a poorer state. Sorry I don’t have the words now to be more precise, but is this the experience of others ,and what are the names of such degradation commonly given?

I am not surprised. For eight bit color, each of the three color channels can have up to 256 color levels (255 if you don’t count ‘0’ as a color). That’s not a lot, and it’s easy to run out of levels. That is, if you apply too much english to your curves you can end up trying to jam a lot of old levels into too few new levels. This causes loss of color.

Jpeg creates 8×8 pixel squares (afaik) that use some sort of algorithm to approximate the original image. As a result, the colors aren’t in exactly the right place in the image. I would assume that this would make curves-caused color deterioration more obvious.

To avoid this, capture all images in RAW or TIFF, then copy to PSD or TIF and manipulate the copy. Use a curves adjustment layer, rather than applying curves to the image itself. (Applying curves directly multiple times will give the same sort of effect as making a photocopy of a photocopy.) When you are ready to publish to web, email, etc, make a JPEG copy.

Now to answer the OP’s question: In either the curves or levels dialog you will see three buttons with icons depicting a full eyedropper, a half-full eyedropper, and an empty eyedropper. The empty eyedropper sets the whitepoint; click it on a pixel that should be pure white. (The other two set neutral gray and the black point.)

Jim Hargan
www.harganonline.com

"Jim Hargan" wrote in message

On Mon, 07 Nov 2005 10:37:45 -0800, John McWilliams wrote:

The best tool I’ve found for removing an unwanted color cast is the Curves command.

While quite true, my conclusions are that with RAW, it’s simple, clean and leaves no bitter after taste…. with JPEGs, large adjustments seem to leave the image in a poorer state. Sorry I don’t have the words now to be more precise, but is this the experience of others ,and what are the names of such degradation commonly given?

I am not surprised. For eight bit color, each of the three color channels can have up to 256 color levels (255 if you don’t count ‘0’ as a color). That’s not a lot, and it’s easy to run out of levels. That is, if you apply
too much english to your curves you can end up trying to jam a lot of old levels into too few new levels. This causes loss of color.

This is the shared belief of many, and although it makes logical and mathematical sense, it is simply not the case when it comes to real photographs. It is a little known fact, for example, that lens flare and internal reflection in the camera reduces the number of significant bits of shadow information that a camera may capture.

Using curves does not cause damage, and although there are some benefits to Raw capture, there is nothing magical about the colors or the amount of data preserved when manipulating RAW images.

On the original topic, curves is the most basic and flexible color correction tool, and one of the most, if not the most powerful method of removing a color cast, whether it be an overall color temperature issue, or color casts due to mixed lighting.
—

Mike Russell
www.curvemeister.com

In article ,
John McWilliams wrote:

While quite true, my conclusions are that with RAW, it’s simple, clean and leaves no bitter after taste…. with JPEGs, large adjustments seem to leave the image in a poorer state. Sorry I don’t have the words now to be more precise, but is this the experience of others ,and what are the names of such degradation commonly given?

JPEG images are degraded in quality. While this degradation is intended to be as unnoticable as possible if an image is not manipulated, certain kinds of manipulation can really exaggerate it. For example, increasing the size of a JPEG via interpolation dramatically increases the appearance of the JPEG artifacts as well.

Dark areas and dark colors in a JPEG tend to be more badly damaged than hilights. Color correction which lightens a JPEG or which kightens certain colors in a JPEG makes the image degradation much more visible.

In general, you want to avoid JPEG whenever possible, and particularly should try to avoid manipulating or color correcting a JPEG whenever possible.

—
Art, photography, shareware, polyamory, literature, kink: all at http://www.xeromag.com/franklin.html

You can try the AGD plugin. It works quite fine. http://www.agdcolor.com/ Petr

"Gordon Pembury" wrote in message

When I shoot RAW I can adjust white balance after I have taken the shot.
Is there an equivalent way of doing that for a JPEG? E.g. by a curves levels or hue/sat type of adjustment. (I know I can adjust the WB in camera before I take the shot, it’s after I’m interested in )
Any help gratefully received

Gordon

On Mon, 07 Nov 2005 19:59:13 GMT, Mike Russell wrote:

Jim Hargan wrote:

That is, if you apply
too much english to your curves you can end up trying to jam a lot of old levels into too few new levels. This causes loss of color.

This is the shared belief of many, and although it makes logical and mathematical sense, it is simply not the case when it comes to real photographs.

I continue with trepidation, for I am going to disagree with Curvemeister, whose knowledge on this subject eclipses mine. Mike, are you assuming that the curves are applied as an adjustment layer? In that case, no argument.

But a few weeks ago I opened a 10 year old scan of a red barn, which had been over-tweaked for saturation. Mid-tone reds had collapsed into one undifferentiated glop. Maybe it’s my lack of skill, but every time I tried to adjust that eye-piercing red, I ended up adjusting the whole barn, as if someone had carefully colored it in with a single crayon. No detail at all.

I also remember (dimly) my Corel Photo-Paint 5 days, when I’d try to lighten shadow areas by changing the slope of the RGB curve, and the midtones would turn a blotchy gray. If I didn’t undo immediately (only one undo level back then), the color detail was gone forever. Once you throw out information, you can’t get it back.

People should *always* use adjustment layers, and *never* alter an original. But when you start learning PS, it’s easy to start fiddling with your image and postpone learning about all those layers and channels. In that case, you can loose information permanently with a really hard tweak.

Or maybe I don’t really have a good grasp on this …

Jim Hargan
www.harganonline.com

Gordon Pembury wrote:

Thank you for a smart arse rersponse!

I know a fair bit about colour adjustment, thanks. The question is, is there a simple way akin to adjustiung whaite balance in RAW for non RAW pictures

"Clyde" wrote in message

Gordon Pembury wrote:

When I shoot RAW I can adjust white balance after I have taken the shot.
Is there an equivalent way of doing that for a JPEG? E.g. by a curves levels or hue/sat type of adjustment. (I know I can adjust the WB in camera before I take the shot, it’s after I’m interested in )
Any help gratefully received

Gordon

Yes, of course. It’s called color adjusting; one of the basic functions of Photoshop. There are many ways of doing that in Photoshop. Pick up a beginning book on Photoshop or do some hunting on the Web.
Clyde

Yeah, sorry about that. Every now and then I get tired of stupid questions in here where the asker obviously hasn’t tried much in Photoshop. Your question seemed to be asking how you could open up JPEG files in ACR. It doesn’t take much trial to learn that you can’t.

I use the CurveMeister plugin to do color correction of all kinds. I even use it to fix "white balance" after opening up a file with ACR. The reason is that it does a better job and does it faster.

I don’t spend a lot of time adjusting colors in ACR. I usually just get the histogram in range and get the color close. For me the automatic settings in CS2’s ACR will pull the histogram in so all the colors are workable. I often manually bump up the saturation a tad. If the color isn’t very close, I’ll play with the presets to see if "Auto" or "daylight" or "Flash" or whatever is better than "As Shot". On occasion
I will use the "White Balance" tool to select a neutral spot in the picture.

So, my process is pretty quick in ACR. As a wedding photographer, I can’t afford to spend too much time. I’m looking for more speed AND better quality.

When I get the picture into CS2 (RAW or JPEG or whatever) the first thing I do is correct the color. I open up the CurveMeister plugin. The basic process is very simple and very fast. I click on the Highlight tool and click on a spot that I think is the highlight. Then I move it. Moving it shows me where the true highlight is in the picture. ACR doesn’t do that speedy little step. Then I do the same with the shadow tool. The last step is to click on the Neutral tool and click on a spot in the picture that I think I neutral. That changes the preview color.

If the overall cast is correct, I’m done. If it isn’t and the picture actually has a neutral in it, I move the neutral point around until I find the best neutral. Usually I’m just watching the overall cast in the preview. When it gets to where I want it, I stop.

For me this is a fast, easy, and accurate way of setting the color cast. Actually the color cast is set with the neutral button. The highlight and shadow button stretch the histogram out to their max.

Besides that speed and accuracy, CurveMeister gives me much more power than that. What I really like are the skin pins. Sometimes the neutral spot in my picture isn’t in the same light as the person’s skin. So setting the while balance on that leaves an odd cast on the person’s skin. I can leave the neutral anchor where it was and pin the person’s skin tone. It sound complicated, but it is as simple as dragging one of the 9 skin tone pins to the person’s skin in the picture. I then move it around until I get the tone I want.

This method gives me "white balance" or color correction in multiple places in the picture. That can be very powerful. Once I start playing with multiple anchors, it does take a little bit more time. If you watch the curve while you are doing this, you can get some very interesting shapes with multiple anchors. You have to watch what gets corrected and what gets worse.

CurveMeister does for me what I think you are looking for. For me it’s faster and better than ACR. It works with any type of file. If there are good competitors to CurveMeister, I don’t know. I bought this because I was used to using Curves in Photoshop; it was an easy step. I recommend it and I’m not in Mike Russell’s pocket in any way. I’ve enjoyed my electronic communication with him and think he’s a good guy with a great product, but all the money has gone his direction.

Thanks,
Clyde

Thanks to everyone, and especially Clyde for the long and informative responses. I’ll have another look at Curvemeister, and at AGD

Many thanks

Gordon

"Petr Kohutek" wrote in message

You can try the AGD plugin. It works quite fine. http://www.agdcolor.com/ Petr

"Gordon Pembury" wrote in message

When I shoot RAW I can adjust white balance after I have taken the shot.
Is there an equivalent way of doing that for a JPEG? E.g. by a curves levels or hue/sat type of adjustment. (I know I can adjust the WB in camera before I take the shot, it’s after I’m interested in )
Any help gratefully received

Gordon