Re: working with sixteen bit scans
Re: working with sixteen bit scans
- Subject: Re: working with sixteen bit scans
- From: "Bruce J. Lindbloom" <email@hidden>
- Date: Wed, 13 Mar 2002 09:51:29 -0600
Neil Barstow wrote:
>
Same thing, yes, but are we sure what it is?
>
A well versed colleague tells me he recently did a test where he
>
distorted the colours of a Gretag input profile by editing it to ensure
>
that the intents were totally identifiable, so RelCol was blue, say,
>
and Percept was green. Next he converted to a WS and surprisingly
>
whatever he did with settings the image came out green.
What I was trying to say was that, unlike output profiles (that have six
tags: A2B0, B2A0, A2B1, B2A1, A2B2, B2A1 that handle three rendering intents
in two conversion directions - to and from the PCS), an input profile can
have only one tag (A2B0). Since the input profile has only one tag, it can
behave in only one way. For output profiles, the A2B0 tag explicitly
represents Perceptual rendering intent. For input profiles, the spec doesn't
actually say what rendering intent this is. It only represents a
device-to-PCS transformation. In my mind, "rendering intent" has to do with
rendering, that is, drawing, printing, displaying, etc. An input profile
does not perform any of these functions, and so I don't think the term
"rendering" is relevant for this type of profile. (But I suppose some will
disagree.)
I had written:
>
I don't think any profiling package makes matrix based input
>
profiles, even though they are allowed by the ICC spec.
Neil responded:
>
Isn't Ektachrome Space different here, it does seem to have more tags
>
when interviewed in Colorthink, unless I'm mistaken.
Joseph Holmes should jump in here, since he is the inventor of Ekta Space.
But from correspondence I have had with him, I understand that he has two
types of Ekta Space -- one that is matrix based (like most working space
profiles and monitor profiles) and one that is LUT based. But Ekta Space is
a working space profile, not an input profile. My comment had to do with
input profiles only.
--
Bruce J. Lindbloom
www.brucelindbloom.com
_______________________________________________
colorsync-users mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/colorsync-users
Do not post admin requests to the list. They will be ignored.