Max, your answer somehow doesn’t fit to my experience. Maybe you can explain my confusion.
Gamut mapping is not needed when the resulting PCS color is inside the gamut of the destination profile.
I agree that mapping is not needed if all colours of the source are inside the destination. But depending on the reproduction aim (rendering intent) a gamut compression is needed (or desired) should some colours be outside. That is e.g. to preserve the overall image „appearance“. But anyhow even if all colours are inside the destination gamut what I see in real life (especially when using the perceptual intent) is gamut compression. Take an RGB image (e.g. the image with the girl in front of the magenta background of the roman16 shows it quite well even on my Macbook Pro display) and convert it to CoatedFOGRA39 (the Adobe CS profile). Then convert it using the perceptual RI to ISO Coated v2 (ECI). The result you see doesn’t fit to what you wrote here, not?
Thus, gamut mapping is not performed for PCS colors within the intersection of the source and destination gamuts.
The source and destination device gamut is identical (as both are based on FOGRA39) but anyhow you’ll see a quite huge color shift in my example. Isn’t the mapping „baked“ into the LUTs and applied by the CMM without any analysis of the actual gamuts? Thanks Claas
Additionally, destination gamut colors outside of the source gamut are not accessed.
For cases utilizing a Smart/Dynamic CMM: It is possible for the CMM to perform rendering/re-rendering along with gamut mapping by taking into account both the source and destination gamuts to achieve various reproduction aims. In this case mapping between non-intercecting regions of the gamuts is possible. However, the extent to which this happens is a proprietary aspect of the smart/dynamic CMM implemeneter.
Max Derhak (PhD) Principal Scientist
-----Original Message----- From: colorsync-users-bounces+max.derhak=onyxgfx.com@lists.apple.com [mailto:colorsync-users-bounces+max.derhak=onyxgfx.com@lists.apple.com] On Behalf Of Roger Breton Sent: Friday, April 01, 2016 10:41 AM To: ''colorsync-users?lists. apple. com' List' Subject: Gamut mapping newbie question
I am told that, gamut mapping only occurs when the Source and Destination gamuts are of different sizes and shape?
Best / Roger
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