New article on color management

Started Apr 26, 2013 | Discussions thread
crames
Regular MemberPosts: 192
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Re: Camera-->sRGB versus Camera-->ProPhoto-->sRGB
In reply to Jack Hogan, Apr 30, 2013

Jack Hogan wrote:

crames wrote:

Speaking of experts, here is a brief article by Jeff Schewe that shows some of the effects of gamut clipping in sRGB and ProPhoto.

One of the early articles that conviced me to use MelissaD65 as a working color space for years, despite the fact that the visible difference was and remains minimal.  Several years later I have two questions in the context of this sub-thread (i.e. Camera-sRGB vs Camera-ProPhoto-sRGB)

1) Can you see a material difference between the two?
2) Even if you did, which one would be more 'correct'?

If you are converting in the usual ways - relative colorimetric intent in PS, standard sRGB and ProPhoto profiles, and without any editing while in ProPhoto to ameliorate gamut clipping, I don't think there will be any visible difference. The correct way under these conditions would be the direct Camera->sRGB, to avoid an extra color space conversion.

Another way to do it is to use the v4 ICC profiles for sRGB and ProPhoto, which contain perceptual intent tables for the purpose of performing a proper gamut mapping to the smaller space. I remember trying them but not getting good results.

Yet another approach was discussed a couple years ago on LuLa by "jc" who developed a method using a profile for an intermediate-sized color space, also having a perceptual table. It seemed to work as advertised. The thread is a little hard to follow, but clarifies a few pages in.

If someone can answer these two questions without bait and switching to answering a different question (is ProPhotoRGB bigger than sRGB?)  we may actually take a step further in the discussion.  In the meantime this is the file in the article opened in ACR 6.7 sRGB, CEP3 Tonal Contrast applied at default settings (left); and the same file opened in ACR 6.7 ProPhotoRGB, CEP3 TC at default and converted to sRGB (right).  I had to actually convert the right file to sRGB after applying TC in order for CS5 gamut warning (gray) to show.

Jeff has posted in this thread, so maybe he will comment.

That'd be great.

Jack

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