Re: working with sixteen bit scans
Re: working with sixteen bit scans
- Subject: Re: working with sixteen bit scans
- From: neilB <email@hidden>
- Date: Wed, 13 Mar 2002 00:25:57 -0800
Hi Bruce
On 12/3/02 at 12/3/02, email@hidden (Bruce J. Lindbloom) wrote:
>
Andrew Rodney wrote:
>
> You can try both intents but I'll bet you, you get Relative Colorimetric
>
> either way. And I don't think BPC will play a factor.
>
>
Yes, I agree. An ICC input profile can only have an A2B0 tag, which
>
is device to PCS. There are no other A2Bx tags, nor are there any
>
B2Ax tags. So no matter what you ask for, I think you will always get
>
the same thing.
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.
Perhaps the <RelCol like> compression we see at the boundary [losing
tonal separation] is a result of the shortcomings of perceptual as
suggested here by Thomas Knoll.
[mainly, I imagine, a result of the weighting of the calculations in
a conversion to the anticipated area of the PCS]??
>
>
On the working space side, ProPhoto RGB is matrix based, so there
>
are no A2B or B2A tags at all. So again, I think you'll always get
>
the same behavior, no matter what rendering intent you request.
>
>
I don't think any profiling package makes matrix based input
>
profiles, even though they are allowed by the ICC spec.
Isn't Ektachrome Space different here, it does seem to have more tags
when interviewed in Colorthink, unless I'm mistaken.
ps thanks for the stuff on your site, nice cartoon too.
"-- "
all the best
neil
Neil Barstow
_______________________________________________
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.