One other thing: what are your Photoshop colour settings?

Also, for an application to be fully colour managed it must use the monitor profile. It is not sufficient to just have the OS be aware of the profile.

Antoine,

When you see the colours change in Windows, than that's the result of calibration. The videoLUT is adjusted in an effort to make the screen neutral. This is not the result of colour management. It's just adjusting the colours.

The screen profile, however, is used by colour managed applications. It describes the device response of the screen (i.o.w. what the calibration process had to do to make it right).

In your case I'm almost certain the profile is bad.

Rob

agarric wrote:

 

How do you know that colors will be out of gammut, What tool do you use?

Well, you look for clipping in the histogram, and look at individual channels to see where the clipping actually occurs. I do this on a copy converted to the target space. Then I decide if the clipping is worth bothering with. It isn't always.

Soft-proofing (Ctrl+Y) is a quicker method, but purely visual.

edited for clarity

I think the OP was entirely correct in his first post - when a monitor is already calibrated _and_ the calibration LUT is already applied (either via the callibrator's own LUT software or by Vista/Win7's LUT loader), colours are wrong, probably because the correction is being applied again (incorrectly) by Photoshop.

Take this scenario:

- We want to author graphics for a non-colour managed application, so we set PS to work in sRGB (this is used by Windows).

- We also have calibrated the monitor for sRGB (in my case using Pantone's Huey).

- The calibration data is loaded into the graphics card LUT (eg. by Windows 7), so the screen is showing sRGB correctly system-wide.

As everything is now set for sRGB, Photoshop _should_ show colours exactly the same as any non-colour managed application - but it doesn't!

I think what's happening is that PS (CS4 in my case) is assuming the monitor calibration data is NOT loaded/applied already, and so applies the calibration conversion a 2nd time!  This behaviour would be correct for earlier versions of Windows as they did not load/apply the monitor calibration data, but it's wrong if it's already applied!

The workaround is to use PS's soft proofing, set for 'Monitor RGB' - now the colours finally look correct. But this is the wrong solution - it is supposed to _bypass_ the monitor calibration.

How can we fix this?

As I understand it, the calibration (to sRGB) corrects the monitor so it displays sRGB accuractely (once the correction is applied to the graphic card's LUT).  So the 'standard state' in this case is sRGB.  I have 4 monitors, all calibrated, all showing colours the same way.

So when PS is in sRGB mode, there is no reason for it to correct its colours again.

And there can certainly be a double-correction, if Photoshop translates the colours before handing them to the graphics card, and then the LUT correction is applied (which is system-wide).  Only older versions of Windows didn't actually apply a LUT system-wide, since Vista Windows does this.

EDIT:  What you may be missing is that sRGB is Windows' own colour mode.  So the calibration devices calibrate to show sRGB accurately (the 'standard state').  So we're not talking about converting between different colours spaces.

I'm afraid you're wrong.  I'm a programmer, and I've written my own LUT loader precisely because XP doesn't load LUTs - you can apply correction profiles to each screen but nothing happens (except in colour-management aware applications).

Vista and Windows 7 _do_ now load LUTs for system-wide correction.

Arrogance is never pretty.

Of course I was talking about an _OS_ LUT loader (if I wrote my own it obviously was possible via 3rd party code).

And that is a system-wide correction, in as much as it corrects all monitors to display sRGB (the native colour space) correctly in all applications.

And your assertion that the calibration only 'sort of' gets you to sRGB is wrong too - think about it, if Photoshop can correct the colours, why can't a cablibration utitlity do the same?  Of course they do, which is why Photoshop should leave the colours alone.

You clearly haven't read my posts carefully.

Full disclosue - I fully understand LUTs, 3D matrices for colour correction etc.  I've been programming graphics for a long time (including graphics card shader stuff).

However I don't intimately know how display profiles work, so see if you agree with this:

- PC monitors are generally designed for sRGB (ignoring wide-gamut displays).

- Calibration utilities produce display profiles with RGB gamma curves to attempt to correct for colour inaccuracies in panels & monitor settings.

- These correction curves are applied system-wide through the use of LUTs on the graphics card (by whatever driver/code).

I have 4 monitors from 3 different vendors, all calibrated with Pantone Huey.  They are very close in their colour display now, which suggests to me that the overall colour balance is reasonably close to sRGB.

However, when I view images in Photoshop, set to sRGB space, with an sRGB document, there is a colour shift.

Are you sure that this shift is correct?  I don't think this happened with PS CS2 on XP (I can go back later to double-check).

Even if I set PS's colour settings to 'Monitor Colour' (via Colour Settings), this shift persists - the only way to eliminate it is via soft-proofing to 'Monitor RGB'.  This simply seems wrong, and if it's not, these colour options are completely unintuitive.

OK, let's keep it simple (I will check my XP/CS2 install later to see if there is a difference in behaviour - I never noticed a shift there with the same setup).

I'm just designing UI graphics for a (non-colour managed) application.  I want to see the colours of my (calibrated) monitors in PS, without any shift (because that's how the final UI will look on them, and my basic monitor calibrations are a better target for me than any more complex preview of a 'theoretical' sRGB mode).

What Photoshop settings would you suggest to achieve this?  You have already agreed that I shouldn't need to soft-proof.

I'll then go and check what is going on.  Thanks Chris.

OK, I have figured out what my issue was - it all resulted from my incorrect assumptions about the sRGB space, ie. that calibrated monitors essentially display sRGB correctly.  I now see that this was wrong and that Photoshop may indeed need to perform an additional conversion to approximate the sRGB space on such displays.  I also found that PS CS2 shows the same behaviour on XP.

In my case, the unexpected colour shift was caused by the document I was working on having an sRGB profile (because of my assumption that sRGB = same as calibrated display).  In this scenario, Photoshop will only show the native monitor colours (without requiring Proof->Monitor RGB) if the Colour Settings are set to 'Monitor Colour' or 'No Colour Management' _and_ the document profile is set to 'Dont colour manage this document'.

Not intuitive - you would assume 'No Colour Management' means that Photoshop performs no conversions at all, yet it still does if the source document is tagged with a profile that doesn't match the display.

It's obvious that colour management is still way too complex for the average user - I'm highly technical with a lot of graphics experience, and you could see how I struggled to get it - how is the average PS user going to figure this out?  Google around, it's obvious many thoughtful people struggle with it and do bad things like remove all colour profiles just to get the result they want.

I appreciate there are good technical reasons for the complexity, however the way this is all exposed to users needs simplifying.  Many users like myself, want to work without colour management in some scenarios, yet they are expected to understand pretty much the entire tangled topic before they can understand which multiple settings are required to achieve it.  A few common-scenario wizards would go a long way to make PS more usable out-of-the-box.

Anyway, thanks for steering me in the right direction Chris.

I had a similar problem, but solution was very simple: in a first line in monitor settings (Color Management tab) I switch value to my new calibrated profile (witch is my default profile after the calibration).

function(){return A.apply(null,[this].concat($A(arguments)))}

function(){return A.apply(null,[this].concat($A(arguments)))}

John Joslin wrote:

<sigh>

John, I can only assume you don't understand the concept behind what I wrote.  I'll be happy to teach you.

If, on the other hand, your "editorial" comments are intended to show how limited my thinking is as compared to your own perfect understanding of the color world, I can only suggest you try to imagine that someone could actually grasp things beyond even the vast sea of your knowledge, out there where the water runs off the flat surface of the planet...  I know it's hard...

-Noel