Re: ICC and Colorspaces
Re: ICC and Colorspaces
- Subject: Re: ICC and Colorspaces
- From: email@hidden
- Date: Fri, 8 Dec 2000 17:16:19 EST
In a message dated 12/8/00 3:17:35 PM, email@hidden writes:
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To see if I understand correctly let's just talk about one of the RGB colors.
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The 255 level readings of red that are in the info pallet refer to 255
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equally
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spaced parts of a red spectrum. The nature of this red spectrum (how
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much is included or excluded) will vary according to the working space
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we're in and that's why simply using the same numbers in another
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colorspace (via assign profile) will produce nonsense. Also if I open a
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file
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that was produced in another colorspace and I choose not to convert to
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my working space I get the same garbage. Ok so far?
Not exactly how I would word it, but yes, you have the concept right...
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Where I'm confused is when I convert to other colorspaces I would expect
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the image on screen to change (less reds to choose from...more reds to
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choose from...wide vs narrow colorspace etc..). But it doesn't.
That is because the conversion keeps the color definitions correct, and as
long s none of the defined colors are outside of any of the spaces involved,
the conversion is successful. Assuming all of the sapces are RGB
workingspaces, if a space is smaller than the data for another space, the
loss will occur in areas that the monitor could not display accurately
anyhow, so no visible change is likely to occur.
And when
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I
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convert to the printer profile after converting to another RGB profile
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I see
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no difference onscreen. Does this suggest that the colors of the test
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image onscreen already fit into most (if not all) user-selectable
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colorspaces and that's why they display the same when converted to other
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color spaces?
Hmmm... I think I just said about the same thing above...
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On another point that's a bit unrelated, would it be silly to choose a
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printer
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profile as the RGB colorspace?
Yes, because it is not a balanced space where R=G=B will offer a neutral
gray, and some similar refinements...
I ask this only because I've seen
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someone set their system up this way (with Photoshop 5.5) and I thought
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this was wrong.
In PS5 it is even more wrong <G> in that you can't accuratey view any kind of
RGB space except an idealized workingspace. With 6 its possible, but not
ideal since your files will end up in a space limited to one pr9inter, with
one inkset and one paper type... not as convenient as choosing the output
space at print time.
C. David Tobie
Design Cooperative
email@hidden