[Jeremy Roussak Gold Member Posts: 1047]

Printing Colour Management

on: May 16, 2024 at 2:09 pm

This is about projector profiles but there doesn’t seem to be any better forum.

My camera club has a Canon projector which we use for visiting speakers and also for the monthly club competitions. Someone recently profiled it; I’m not sure what kit he used. He’s sent me the resulting profile, which to my eyes produces results indistinguishable from the Apple-supplied profile for this projector.

He’s now suggesting that the profile needs to be re-done and wondering if we need to splash out on a better piece of kit to do it. Before we spend any money, I’d like to compare his profile with the Apple-supplied profile using a rather better and more objective tool than my eye.

Is there some (preferably free) software which will compare two .icm profiles and give some indication, meaningful to an ignoramus (me), how similar / different they are?

Jeremy

[Mark D Segal Silver Member Posts: 951]

Re: Comparing profiles?

Reply #1 on: May 16, 2024 at 2:48 pm

I don’t know how this would work in the specific case of projectors, but in general the usual way we compare the accuracy of profiles is with bespoke software that runs a set of patches through the profiles and calculates an average and patch-specific dE comparing the references values for the patches with the colour values rendered by the device. Whichever profile shows the lowest dE value would be the more accurate, but to interpret such results you need to know how to relate the dE values to actual perceptions of inaccurate colours.

[Andrew Rodney Participant Posts: 416]

Re: Comparing profiles?

Reply #2 on: May 16, 2024 at 2:57 pm

What “Apple Projector” profile?

One can profile a projector using an EyeOne Beamer (a device and an EyeOne Spectrophotometer). It works fairly well only using color-managed applications and only one source, meaning the projector and not the display of the computer. One mirrors the two, only one uses the profile. So if the projected data through the profile looks good, the display looks awful. Noting you can do about that.
Compare profiles for free, well sure, the Apple ColorSync utility will do this, at least in terms of viewing color gamut. Which doesn’t tell you anything useful about ‘accuracy’ or even the desired color. So I’m not sure what good that would do you. Profile the projector. Pass a known color reference image through it and view the results subjectively. That’s about all you can really do. Again, always use a color-managed application to apply said profile, through data, to the screen (s).

Author “Color Management for Photographers" & "Photoshop CC Color Management" (pluralsight.com)”

[Jeremy Roussak Gold Member Posts: 1047]

Re: Comparing profiles?

Reply #3 on: May 19, 2024 at 11:33 am

I’m less interested in the absolute accuracy of the profiles than in whether the custom profile that the club has made is significantly different from the Apple-supplied profile for this particular projector; my interest is financial. I’ll have a look at ColorSync.

Jeremy

[Andrew Rodney Participant Posts: 416]

Re: Comparing profiles?

Reply #4 on: May 19, 2024 at 11:43 am

Upload the two and I can ploto them in ColorThink Pro. Or you can do a similar comparison (of simply the color gamut) using the ColorSync Utility if you have a Mac.

Author “Color Management for Photographers" & "Photoshop CC Color Management" (pluralsight.com)”

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