Re: Photoshop Gamut warning vs ColorThink
Re: Photoshop Gamut warning vs ColorThink
- Subject: Re: Photoshop Gamut warning vs ColorThink
- From: Chris Cox <email@hidden>
- Date: Fri, 22 Feb 2008 13:02:32 -0800
- Thread-topic: Photoshop Gamut warning vs ColorThink
> Date: Thu, 21 Feb 2008 15:25:10 -0800
> From: Steve Upton <email@hidden>
> Subject: Re: Photoshop Gamut warning vs ColorThink
>
> I do not think that gamut warning should vary by the output intent (including
> BPC).... or perhaps the UI should change to allow more informed intent
> choices.
The gamut warning has to change with intent -- because the colors that will
be in gamut after the conversion depend entirely on what intent was used to
make the conversion.
It really doesn't matter if the color is in gamut BEFORE I convert, what
matters is if the color will be in gamut AFTER I convert to that colorspace
using my chosen options. If I tried to manually bring colors into gamut
using the absolute gamut for the device (corresponding to absolute
colorimetric intent), then converted using perceptual intent -- I don't
think I'd get what I was looking for. Instead I'd get something that was
desaturated and contrast reduced TWICE (once by me, and once by the
perceptual intent conversion). What I want is to know what might be clipped
or otherwise damaged using the intent and options that I will use for the
final conversion.
Quick analogy: If I'm trying to get to Topeka, what matters is if I land
in Topeka or Omaha - not that I started the trip in Tokyo.
> While I do understand that different intents will affect the resulting image
> gamut, overall I feel it is the job of soft proofing rather than gamut warning
> to inform the user.
I disagree: users want to know what will be in gamut or not in their final
output. And that means you have to take their intent and other options into
account.
> To me, gamut warning is about how my image relates to the gamut of my output
> device. The warning informs me (hopefully) which colors are out of gamut and
> likely to be affected the most. I can then make different decisions such as
> changing the rendering intent (possibly introducing changes to all my colors
> because of my desires for specific colors) or even changing papers or devices.
But that is what Photoshop shows you: What will be in gamut or not
depending on the options you choose. You change intents, you see the
resulting change on your image. There aren't many people who could look at
absolute LAB values and decide what intent and options would be best for
their image without feeedback (in fact, I think all of us who qualify have
been out drinking together).
> A gamut warning that is determined from a chosen intent (or intents in a round
> trip), tells me how a specific intent's resulting gamut relates to my image.
> Unfortunately it does so in a threshold manner, implying a true/false in/out
> good/bad judgement that isn't really there. As a user, I think I'm mislead as
> I am receiving a mixed message.
True, Photoshop could provide more of a "X deltaE out of gamut" display
instead of the current binary form. It's just not trivial to overlay such
information on a full color image (unless you have another color we can use
that doesn't appear in the image :-). But a binary "out of gamut" warning
has a lot of value in deciding how much manual adjustment you need, or
whether you need to change your rendering intent or other options.
So, for those who don't find Photoshop's gamut warning useful: what other
information could we provide to help you? What is missing?
Chris
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