Is Adobe Gamma appropriate for TFTs?

Gary wrote:

I heard that Adobe Gamma was specifically for "tubes". Is this so? If so, what else can we calibrate our moitors with?

Adobe Gamma is a working space – which means it is a storage, not a display specification.

Calibration is done using Adobe Gamma, and the resulting profile is saved for later use by Photoshop and other color aware Adobe apps. For this procedure you may use any working profile you wish, typically the choices are Adobe Gamma, sRGB, Colormatch, and Apple RGB.

The first two working spaces are typically used on Windows, and the last two on the Macintosh because the overall brightness (gamma) of those workspaces looks good on the monitors of the respective systems.

I use sRGB as my working space because Adobe RGB images appear drab when viewed outside of Photoshop. Others choose Adobe RGB, and their reasons include the wider gamut of that color space, and they are less concerned about how their images might appear to less initiated people.

Before the
flames start, I already tried a banana and the top of a pepsi bottle.

But do they have aluminum foil hats on? 🙂
—

Mike Russell
www.curvemeister.com
www.geigy.2y.net

It sure sounds like Mike is confusing "Adobe Gamma" (the monitor calibration utility) with "Adobe RGB" (the working space) … think about it.

Bill

Gary wrote:
I heard that Adobe Gamma was specifically for "tubes". Is this so?

From: "Mike Russell"

Adobe Gamma is a working space – which means it is a storage, not a display specification.

"Gary" wrote in message

I heard that Adobe Gamma was specifically for "tubes". Is this so? If

so,

what else can we calibrate our moitors with? Before the flames start, I already tried a banana and the top of a pepsi bottle.

That’s my understanding too. I don’t know of any utility like Adobe Gamma which is designed to work
with TFTs, and I’d be interested if there is something available. I have read that TFTs can often have an
"S" response, and that’s part of the reason why Adobe Gamma won’t work well. I do wonder
though whether modern TFTs might be better behaved, and be more linear in their native response?

You probably know this already, but you can use a calibration package which is specifically designed
to work with TFTs. (Eye One Display, Spyder, etc)

Greg.

"Mike Russell" wrote in message

Adobe Gamma is a working space – which means it is a storage, not a

display

specification.

[snip]

For this
procedure you may use any working profile you wish, typically the choices are Adobe Gamma, sRGB, Colormatch, and Apple RGB.

Anybody else want to step in and help the Curvemeister learn the difference between Adobe Gamma, working spaces and profiles?

—–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– http://www.newsfeeds.com – The #1 Newsgroup Service in the World! —–== Over 100,000 Newsgroups – 19 Different Servers! =—–

"Flycaster" wrote in message

Anybody else want to step in and help the Curvemeister learn the

difference

between Adobe Gamma, working spaces and profiles?

I reckon someone else was at his keyboard, playing a trick on him. 🙂

Greg.

Bill is correct, and not for the first time. – Adobe RGB is a working space, Adobe Gamma is the utility for setting up your monitor and it’s working space.
—

Mike Russell
www.curvemeister.com
www.geigy.2y.net

Bill Hilton wrote:

It sure sounds like Mike is confusing "Adobe Gamma" (the monitor calibration utility) with "Adobe RGB" (the working space) … think about it.

Bill

Gary wrote:
I heard that Adobe Gamma was specifically for "tubes". Is this so?

From: "Mike Russell"

Adobe Gamma is a working space – which means it is a storage, not a display specification.

In article <4011d165$
says…

"Mike Russell" wrote in message

Anybody else want to step in and help the Curvemeister learn the difference between Adobe Gamma, working spaces and profiles?

In simple terms, and probably not 100% accurate (please correct me where necessary!):
A profile (specifically an ICC profile) is a set of information that describes the colour characteristics of a device or a working space, relative to a theoretical absolute (e.g. LAB colour space). The term ‘colour space’ is also often used to describe this colour information. All profiles contain a subset of all possible colours from LAB space. If it contains a fairly large subset it is a wide colour gamut.
For a scanner or digicam, the profile describes what absolute (e.g. LAB) colour is represented by each set of RGB values produced by the device.
For a monitor, the profile describes what absolute (e.g. LAB) colour it will display for each value set of RGB values it is given.
For a printer, the profile describes what absolute (e.g. LAB) colour it will print for each value set of RGB values it is given.

A working space is the profile assigned to an image while you work on it. It is not strictly needed, but is useful. For example – if the image was edited in, say, the scanner profile you would find that equal values of R, G and B did not
represent a neutral colour, making tools like the eyedropper in ‘Levels’ almost useless. Working space profiles are well behaved (equal RGB values are always neutral) and have a defined white point (e.g. what LAB colour is 255,255,255), normally described as a temperature (e.g. 5000K). Typical working profiles are Adobe RGB (fairly wide gamut) and sRGB (rather narrower).

Adobe Gamma is an application. It lets you calibrate a monitor by you setting the brightness, contrast, etc., and by loading a colour LookUp Table (LUT) to the graphics card on startup. It also creates a monitor profile to describe the calibrated monitor and sets that profile as the default for your monitor. Photoshop will automatically use this default monitor profile to compensate the RGB values it sends to the graphics card, in order that you see the correct colours for the profile (working space) of the image.

Phew… HTH 🙂

"Graeme Cogger" wrote in message

In article <4011d165$
says…

"Mike Russell" wrote in message

Anybody else want to step in and help the Curvemeister learn the

difference

between Adobe Gamma, working spaces and profiles?

In simple terms, and probably not 100% accurate (please correct me where necessary!):
A profile (specifically an ICC profile) is a set of information that describes the colour characteristics of a device or a working space, relative to a theoretical absolute (e.g. LAB colour space). The term ‘colour space’ is also often used to describe this colour information. All profiles contain a subset of all possible colours from LAB space. If it contains a fairly large subset it is a wide colour gamut.
For a scanner or digicam, the profile describes what absolute (e.g. LAB) colour is represented by each set of RGB values produced by the device.
For a monitor, the profile describes what absolute (e.g. LAB) colour it will display for each value set of RGB values it is given.
For a printer, the profile describes what absolute (e.g. LAB) colour it will print for each value set of RGB values it is given.

A working space is the profile assigned to an image while you work on it. It is not strictly needed, but is useful. For example – if the image was edited in, say, the scanner profile you would find that equal values of R, G and B did not
represent a neutral colour, making tools like the eyedropper in ‘Levels’ almost useless. Working space profiles are well behaved (equal RGB values are always neutral) and have a defined white point (e.g. what LAB colour is 255,255,255), normally described as a temperature (e.g. 5000K). Typical working profiles are Adobe RGB (fairly wide gamut) and sRGB (rather narrower).

Adobe Gamma is an application. It lets you calibrate a monitor by you setting the brightness, contrast, etc., and by loading a colour LookUp Table (LUT) to the graphics card on startup. It also creates a monitor profile to describe the calibrated monitor and sets that profile as the default for your monitor. Photoshop will automatically use this default monitor profile to compensate the RGB values it sends to the graphics card, in order that you see the correct colours for the profile (working space) of the image.

Phew… HTH 🙂

You know your stuff. Great job, and I look forward to seeing more of your posts.

—–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– http://www.newsfeeds.com – The #1 Newsgroup Service in the World! —–== Over 100,000 Newsgroups – 19 Different Servers! =—–

Like a previous poster, I struggle with the color space/profile/calibration concept. From 1) a digital camera or scanner, to 2) Photoshop (as presented by a monitor), to 3) a printer. And then there’s "proof setup." Which of these should be considered the starting place, or driving force?

"Graeme Cogger" wrote in message

In simple terms, and probably not 100% accurate (please correct me where necessary!):
A profile (specifically an ICC profile) is a set of information that describes the colour characteristics of a device or a working space, relative to a theoretical absolute (e.g. LAB colour space). The term ‘colour space’ is also often used to describe this colour information. All profiles contain a subset of all possible colours from LAB space. If it contains a fairly large subset it is a wide colour gamut.
For a scanner or digicam, the profile describes what absolute (e.g. LAB) colour is represented by each set of RGB values produced by the device.
For a monitor, the profile describes what absolute (e.g. LAB) colour it will display for each value set of RGB values it is given.
For a printer, the profile describes what absolute (e.g. LAB) colour it will print for each value set of RGB values it is given.

A working space is the profile assigned to an image while you work on it. It is not strictly needed, but is useful. For example – if the image was edited in, say, the scanner profile you would find that equal values of R, G and B did not
represent a neutral colour, making tools like the eyedropper in ‘Levels’ almost useless. Working space profiles are well behaved (equal RGB values are always neutral) and have a defined white point (e.g. what LAB colour is 255,255,255), normally described as a temperature (e.g. 5000K). Typical working profiles are Adobe RGB (fairly wide gamut) and sRGB (rather narrower).

Adobe Gamma is an application. It lets you calibrate a monitor by you setting the brightness, contrast, etc., and by loading a colour LookUp Table (LUT) to the graphics card on startup. It also creates a monitor profile to describe the calibrated monitor and sets that profile as the default for your monitor. Photoshop will automatically use this default monitor profile to compensate the RGB values it sends to the graphics card, in order that you see the correct colours for the profile (working space) of the image.

Phew… HTH 🙂

Linelle Lane wrote:

Like a previous poster, I struggle with the color
space/profile/calibration concept. From 1) a digital camera or scanner, to 2) Photoshop (as presented by a monitor), to 3) a printer. And then there’s "proof setup." Which of these should be considered the starting place, or driving force?

A lot of people find the concepts elusive, and with good reason (even without people like me posting typographical errors on the subject :-). There are several variables that can be changed, and a large quantity of products and suggestions on what to change to get better color.

A simpler solution, that I recommend for those just starting out, is to set your working space to sRGB, and print to your printer using a generic sRGB driver setting, which is available with most printers. With my Epson 1270, I use PhotoEhhance4 and get excellent results – better than any of the profiles I have tried.

One of the better summaries of how to correctly configure Photoshop with profiles, from a photographer’s point of view, can be found on Ian Lyon’s web page:

http://www.computer-darkroom.com/ps7-colour/ps7_1.htm

The above link is for PS7, and there are additional links for PS6 and CS, and a large number of other thoughtful articles. Ian also has some good quality profiles for certain Epson printers.

I would recommend you get the simpler sRGB config set up first, and then, provided you see any problems with the results, change things one at a time to get closer to the profile based setup documented on Ian’s page.

—

Mike Russell
www.curvemeister.com
www.geigy.2y.net

The rest of the posts on this thread, have gone off to discuss colour space, I would however be interest in an answer to the original question, about the relevance of the gamma function to TFT’s displays.

Jeffrey
"Gary" wrote in message

I heard that Adobe Gamma was specifically for "tubes". Is this so? If

so,

what else can we calibrate our moitors with? Before the flames start, I already tried a banana and the top of a pepsi bottle.

Gary

"Jeffrey" wrote in message

The rest of the posts on this thread, have gone off to discuss colour

space,

I would however be interest in an answer to the original question, about

the

relevance of the gamma function to TFT’s displays.

Well, I may have been one of the guilty parties. Here’s what I know (based on personal experience):
I have yet to see a TFT that can be accurately calibrated for decent color and contrast, irrespective of using Adobe Gamma, or a puck based system. To be sure, I have not seen, much less tried to calibrate one new high-end (as in $$$) LCD’s or newer high-end laptop TFT displays. Some folks that have seen them say they work great, others say differently.

All I can say is my laptop (a year old Dell 8100) is completely *useless* for accurate image manipulation, other than by-the-numbers (for those of you who remember 4.0, you’ll know what I talk about). It does, however, work great for storage and simple batch work that ultimately saves me a bunch of time later once I return from a trip.

—–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– http://www.newsfeeds.com – The #1 Newsgroup Service in the World! —–== Over 100,000 Newsgroups – 19 Different Servers! =—–

ta, thanks for your reply.

I have a Toshiba Sattleite Pro 6100, while it gives pretty good colour and is handy as you suggest for portable data holding, the quick edit/check, I have not much confidence about colour matching or even gamma correction, partcularly when the colour seems to change depending upon the angle you looking at it.

Jeffrey
"Flycaster" wrote in message

"Jeffrey" wrote in message

The rest of the posts on this thread, have gone off to discuss colour

space,

I would however be interest in an answer to the original question, about

the

relevance of the gamma function to TFT’s displays.

Well, I may have been one of the guilty parties. Here’s what I know

(based

on personal experience):
I have yet to see a TFT that can be accurately calibrated for decent color and contrast, irrespective of using Adobe Gamma, or a puck based system.

To

be sure, I have not seen, much less tried to calibrate one new high-end

(as

in $$$) LCD’s or newer high-end laptop TFT displays. Some folks that have seen them say they work great, others say differently.

All I can say is my laptop (a year old Dell 8100) is completely *useless* for accurate image manipulation, other than by-the-numbers (for those of

you

who remember 4.0, you’ll know what I talk about). It does, however, work great for storage and simple batch work that ultimately saves me a bunch

of

time later once I return from a trip.

—–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– http://www.newsfeeds.com – The #1 Newsgroup Service in the World! —–== Over 100,000 Newsgroups – 19 Different Servers! =—–

In article <_YCQb.15446$>,
says…

Linelle Lane wrote:

Like a previous poster, I struggle with the color
space/profile/calibration concept. From 1) a digital camera or scanner, to 2) Photoshop (as presented by a monitor), to 3) a printer. And then there’s "proof setup." Which of these should be considered the starting place, or driving force?

A lot of people find the concepts elusive, and with good reason (even without people like me posting typographical errors on the subject :-). There are several variables that can be changed, and a large quantity of products and suggestions on what to change to get better color.

I couldn’t agree more – it is very confusing and I can’t help but feel there must be a simpler way of doing things. It’s also worth noting that ‘good practice’ can’t really be
introduced in stages. Until at least the monitor and printer are calibrated/profiled properly, changing to the ‘correct’ way of doing things is just as likely to make things worse as it is better.

<snip>

I would recommend you get the simpler sRGB config set up first, and then, provided you see any problems with the results, change things one at a time to get closer to the profile based setup documented on Ian’s page.

Good advice. I’d make sure you have at least a decent monitor and printer/paper/ink profile before making any changes.

In article <40130c3b$0$26115$>,
says…

The rest of the posts on this thread, have gone off to discuss colour space, I would however be interest in an answer to the original question, about the relevance of the gamma function to TFT’s displays.

Jeffrey

Adobe Gamma does not generally work well with TFT monitors, although it wasn’t too bad on my Sharp LL-T1620 so it’s worth a try. There are various ‘cheap’ calibration systems available that manage TFT’s pretty well, but they cost around $200 or more.

Greg wrote:

I have read that TFTs can often have an "S" response, and that’s part of the reason why Adobe Gamma won’t work well.

I don’t see an "S" response on my TFT but I’m definitely not seeing a linear tone response either. No monitor has a linear tone response, as far as I know.

I do wonder though whether modern TFTs might be better behaved, and be more linear in their native response?

I can only speak for myself of course, but I’ve been using a TFT as my primary monitor for the last 5 or 6 months or so, and I’m never going back to a CRT again. I do have a CRT monitor too, but the TFT has so many advantages over the CRT, that I can live with the slightly smaller gamut of the TFT compared to the CRT.

What people often don’t realize is the fact that there’re many different TFT panels out there with very different specifications. In the cheapest TFT’s, you’ll often find MVA, TN and TN+ panels. They seem to have nice specs. _on the paper_, but compared to TFT’s with IPS and S-IPS panels, they’re often worth nothing when it comes to colours. You won’t find IPS and S-IPS panels in the cheap TFT’s. Only the more expensive ones (like the Apple Studio Display for instance) has IPS or S-IPS panels.

On the following link you’ll see the tonal response and the correction that OptiCAL makes to my TFT. (I calibrate it to a gamma of 2.2 and native as the whitepoint, which is around 6050K according to OptiCAL although the onscreen display of the monitor says 6500K, which is the default setting).

<http://home18.inet.tele.dk/madsen/monitor/calibration> (It’s a Viewsonic VP201a TFT with an IPS panel).

—
Regards
Madsen.

"Thomas Madsen" wrote in message

Greg wrote:

I have read that TFTs can often have an "S" response, and that’s part of the reason why Adobe Gamma won’t work well.

I don’t see an "S" response on my TFT but I’m definitely not seeing a linear tone response either. No monitor has a linear tone response, as far as I know.

I see an incy wincy bit of an S response – there’s a kink right up near the top of the scale. 🙂
Seriously though, yes, it does look very well behaved. (CRT-like)

Regarding "linear", I just meant perceptually linear. I realise that a CRT has a non-linear
response in terms of absolute light level vs voltage.

Greg.

Greg wrote:

Regarding "linear", I just meant perceptually linear.

Ahh, okay. 🙂

—
Regards
Madsen.

On Sun, 25 Jan 2004 01:42:25 -0000, Graeme Cogger
wrote:

In article <40130c3b$0$26115$>,
says…

The rest of the posts on this thread, have gone off to discuss colour space, I would however be interest in an answer to the original question, about the relevance of the gamma function to TFT’s displays.

Jeffrey

Adobe Gamma does not generally work well with TFT monitors, although it wasn’t too bad on my Sharp LL-T1620 so it’s worth a try. There are various ‘cheap’ calibration systems available that manage TFT’s pretty well, but they cost around $200 or more.

Adobe Gamma worked fairly well on my ViewSonic VX2000 (21" LCD), but Optical/SpyderPro worked better IMHO.

On Sun, 25 Jan 2004 03:15:07 +0100, Thomas Madsen
wrote:

What people often don’t realize is the fact that there’re many different TFT panels out there with very different specifications. In the cheapest TFT’s, you’ll often find MVA, TN and TN+ panels. They seem to have nice specs. _on the paper_, but compared to TFT’s with IPS and S-IPS panels, they’re often worth nothing when it comes to colours. You won’t find IPS and S-IPS panels in the cheap TFT’s. Only the more expensive ones (like the Apple Studio Display for instance) has IPS or S-IPS panels.

For those like me who aren’t clear what these acronyms mean, check <http://www4.tomshardware.com/display/20020114/lcd-04.html> for a short intro. (One of the very few in English – why is it that there is lots of discussion of TFT types in German, Polish, Chinese and Japanese, but almost none in English?)

But they don’t mention S-IPS – do you have a link or clue what this adds?

When you mention the "Apple Studio Display" as being IPS or S-IPS, I don’t suppose that includes my original 15" Bondi Blue model with the Apple connector (as opposed to the PC-VGA connector on later colors)? Or does it? Can one tell by looking?

Loren

Loren Amelang wrote:

(One of the very few in English – why is it that there is lots of discussion of TFT types in German, Polish, Chinese and Japanese, but almost none in English?)

I don’t understand it either, but you’re right. I’ve noticed the same thing.
<http://www.meko.co.uk/ipswitch.shtml> tells a little about IPS and MVA panels but that’s all I’ve ever found on an English site (besides tomshardware.com). Many sites doesn’t seem to know that there’re different TFT types out there.

But they don’t mention S-IPS – do you have a link or clue what this adds?

As far as I know, S-IPS is newer than IPS and has improved colour purity, higher viewing angels and quicker response times over IPS panels. I don’t know if you understand German, but you can find it mentioned here: <http://www.prad.de/new/lexikon/s-ips.html>.

When you mention the "Apple Studio Display" as being IPS or S-IPS, I don’t suppose that includes my original 15" Bondi Blue model with the Apple connector (as opposed to the PC-VGA connector on later colors)? Or does it? Can one tell by looking?

When I mentioned the Apple Studio Display, I meant these: <http://www.apple.com/displays/>. They only come in 17", 20" and 23", and I’m not sure whether they have IPS or S-IPS panels, but I’ve heard from different sources that it’s either IPS or S-IPS. Their specifications indicates that it’s probably IPS with viewing angles of 170°(horizontal and vertical), brightness of 200 cd/m² and contrast ratios around 350:1. That’s very typical specs. for IPS panels.
My sister has the 23" Apple Studio Display, an as far as we can see, it’s very similar to my Viewsonic VP201s(*) when we compare them to each other, so I’m pretty sure that the Apple Studio Displays has either IPS or S-IPS panels.

(*) I wrote VP201a in <news:>
but that was a typo. The name is VP201s.

—
Regards
Madsen.