input tags, was Re: working with sixteen bit scans
input tags, was Re: working with sixteen bit scans
- Subject: input tags, was Re: working with sixteen bit scans
- From: Steve Upton <email@hidden>
- Date: Thu, 14 Mar 2002 01:11:03 -0800
At 9:51 AM -0600 3/13/02, Bruce J. Lindbloom wrote:
>
<snip>
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have only one tag (A2B0). Since the input profile has only one tag, it can
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behave in only one way. For output profiles, the A2B0 tag explicitly
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represents Perceptual rendering intent. For input profiles, the spec doesn't
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actually say what rendering intent this is. It only represents a
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device-to-PCS transformation. In my mind, "rendering intent" has to do with
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rendering, that is, drawing, printing, displaying, etc. An input profile
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does not perform any of these functions, and so I don't think the term
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"rendering" is relevant for this type of profile. (But I suppose some will
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disagree.)
not to split hairs here.... ok to split hairs
Is it not more correct to say that the input profile is 'required to have' only one LUT tag (of those that have LUT tags).
A profile can really contain many additional tags whether they are ICC defined or not. I have certainly found that some input profiles do indeed contain other A2Bn tags although they never seem to get used - which is understandable as they are not expected by the CMM.
I agree with your interpretation of the term 'rendering' here and I often refer to the device->PCS link as the proofing transform - although this term falls short when used to describe input and monitor profiles... oh well.
I have found that some input profiles "gamut boundaries" have a working-space symmetry to them while others have a more natural looking, convoluted surface. This seems to be the signature of the profile generation s/w as they will differ for the same device... always thought that a little odd.
Regards,
Steve
________________________________________________________________________
o Steve Upton CHROMiX www.chromix.com
o (hueman) 866.CHROMiX
o email@hidden 206.985.6837
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