CHROMiX

Why do color-managed applications use the monitor profile?

I have been struggling with the following for a long time, asked many people, posted many queries, yet never received a good answer. I just discovered this forum and hope that someone here can help.

I made a profile for my monitor using the EyeOne Display 2 device. My understanding is that this profile is used to modify my video card’s lookup table at boot time. It is system-wide and applies to all images displayed by all applications, color-managed (Lightroom, Photoshop) or not (most browsers, IrfanView).

I understand further that color-managed applications consider the source profile, the profile that is included in an image, if one is available. That makes sense.

However, I observe that color-managed applications are also considering the monitor profile. That is, the color displayed on my monitor by a color-managed applications changes as I change the monitor profile. I’m doing this change after boot time such that the LUT is not changed, only the monitor profile considered by the application.

Why is this? Why would a color-managed application look at the monitor profile when that profile has already been applied to the image in the form of a LUT correction? It looks like double profiling to me.

A brief background explanation… I came to observe this because a defect in my EyeOne colorimeter produced a defective monitor profile that had a strongly exaggerated color shift. The shift before the defect occurred was far less and I never noticed the difference between the images displayed by color-managed applications and non-color managed ones. But with the defect the shift was pronounced and led me to track down the source, which I discovered was a bogus monitor profile. Observing the colors displayed by color-managed apps as I moved the defective profile in and out confirmed the cause.

The only thing I can come up with is that I am indeed applying the monitor profile twice and that I should not be using the EyeOne software at boot time to modify the LUT when I’m using it with color-managed apps. I’m afraid that that this not a satisfying explanation because I can’t understand why the EyeOne, a reputable device from a reputable company, would create a situation that, by default, results in double profiling.

Thanks much,
Bill

It’s not double profiling as much as it is what we call “round-tripping”. When you think about it, a lot of profiles are used in pairs and the monitor system is no exception. When your image is in the Photoshop working space, the working space profile is used to transform the color into Lab space (the “universal translator” for color.) Then the monitor profile does the job of converting the color out of Lab and into the proper color to be displayed on your monitor.

Also consider that Photoshop needs to be able to handle colors that are outside of the monitor space, so they are displayed with some sort of normalcy. The monitor profile conversion helps this to happen smoothly.

Also consider the gamma of the calibration / profile. When looking at non-color managed apps you will see the effect of the gamma you have chosen (2.2 or 1.8 or whatever). Photoshop, through the monitor profile, will round trip this gamma correction so that your contrast is exactly what it should be, without any artificial curve. In PS, you don’t see any gamma effect.

This is a complicated topic, and is not very widely discussed, so I hope this helps some.

Hi All, just signed up here!

I’ve read my eyes to burning red on color, spaces, profiles, management. Fascinating and hugely complicated! I bump this older thread as there are a few things I still can’t get my head around related to this discussion. :unamused:

I have a ThinkPad T61 laptop with a 1440 x 900 screen calibrated with Spyder3Pro. Win XP Pro SP3. My issue/question is only about colors on screen.

I shoot images in RAW sRGB > then Process in Lightroom (that uses PhotoPro internally) > then export to JPG sRGB in 100% quality. I find it very frustrating that a lot of images look a little or very different when viewed in Windows IE or the file viewer. The Firefox browser supports color management and I pointed Firefox to my monitor profile and images are rendered identical to Lightroom and Photoshop.

Coming to my question; the monitor calibration/profile works throughout the system. For Windows and for ‘color aware’ apps like Lightroom and - in this case - Firefox. So what causes the different colors viewing one and the same JPG file???

I’ve been cracking my head over this and it drives me nuts… :laughing:

Richard.