Re: Theoretical CMYK Profile "and Lch"
Re: Theoretical CMYK Profile "and Lch"
- Subject: Re: Theoretical CMYK Profile "and Lch"
- From: Roger Breton <email@hidden>
- Date: Wed, 17 May 2006 22:32:34 -0400
Oscar,
> You say that to you and all the color people you know, LCH is more
> user friendly.
My very experience.
> Unfortunately the color people at Adobe have taken the
> "Working Space RGB" route way back
For historical reasons we understand.
> which seems to suggest that not
> everybody agrees.
We know that Photoshop has not always been CIE-based, though.
> From a user's perspective this may not be so stupid
> after all:
I never said RGB was stupid, only that Lch has a superior quality to Lab in
terms of carrying color apperance information to the user.
> Memory colors are useful if named as such. That is, to adjust from or
> to a memory color will likely involve some kind of menu selection
> with named colors. How these colors are stored is irrelevant from a
> user's perspective. It would make sense to use a reference space such
> as XYZ or Lab, but having LCH values is totally irrelevant.
Wow, that's an extreme point of view, Oscar. How is Lch "totally irrelevant"
for forming judgement about color appearance to you?
> This is
> perfectly illustrated by the Photofilters in Photoshop which seem to
> be stored relative to Lab, but can be accessed/adjusted using any
> colorspace.
I don't debate the underlying color architecture of the tools and I don't
demand that Adove comes up with Lch flavors of the same tools or different
tools. All I ask for is the alternative of having the information presented
in Lch in the Info palette, that's all. Not a big change. But a useful
change, nonetheless. Remember the Hollywood movie starring Kevin Costner
which said : "if you build it it will come"? Well, that's what I think will
happen. If the tool is not there how can people, including yourself and many
others, get in the habit of checking colors by Lch? CIE Lab is nice and
there are lot's of time I will switch to Lab over Lch for certain color
processing tasks. But Lch is a very powerful perceptual metaphor.
> Note also that we have yet to see the first device with ProPhotoRGB,
> so saying that RGB is not device-independent is somewhat of a
> misnomer.
I'm confused. But I'll respect your opinion.
> For all practical purposes it is as good as a reference
> space as Lab.
Again, you have all my respect.
> Most of the time your images are processed in some RGB
> space, and therefore the memory colors (and Photo filters) should
> preferably be accessed in that space.
Do you mean that you have come to associated sky, foliage and skin with
certain RGB triplets? ProPhoto RGB triplets?
> Whether the reference behind
> the colors is some "device-independent" reference space is irrelevant
> to the user.
The problem arises the moment edits to those memory colors occur in
difference color space, what do you do then? Say you open a CMYK image and
there are some grass in this image. What then? How can you form a judgement
on the color appearance of grass in this CMYK image? The way I see it, you
need to learn another set of device numbers to be able to say anything
useful about the memory colors in that image, no? Don't you find a waste of
having to learn different sets of numbers for different kinds of color
spaces, for the same memory colors?
> And in addition, adjusting the colors in that same RGB
> space is far easier using some HSB (or HLS) equivalent.
Device coordinates.
> Just playing the devil's advocate here,
Well done. I hope someone at Adobe is monitoring the discussion.
> Regards,
> Oscar
Regards,
Roger Breton | Laval, Canada | email@hidden
http://pages.infinit.net/graxx
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