Re: Managing Merge Colors in Photoshop
Re: Managing Merge Colors in Photoshop
- Subject: Re: Managing Merge Colors in Photoshop
- From: Graeme Gill <email@hidden>
- Date: Wed, 01 Dec 2004 22:53:34 +1100
- Organization: Color Technology Solutions Pty. Ltd.
Roger Breton wrote:
It is plain to see that some compression is going on. Perhaps Photoshop is
using the PMS Lab values assigned to each spot channels as a Source in the
conversion and is matching to whatever CMYK working space currently selected
as the implicit Destination. I'd just wish that was explicit or documented
somewhere.
I'd be rather surprised if it was documented. Most of that sort of stuff
is black magic.
The approach I used for this sort of operation in Cyclone was to convert
the Lab to CMYK values (clipping to the gamut if necessary), and then
applying a CMYK mixing model to compute tints and tint combinations,
finally doing ink limiting on the result.
A spectral ink mixing model would be better (ie. predicting what
the overlay of all the spot inks is going to be on a theoretical
press), and then converting that Lab into CMYK, but you need the
spectral information for the inks to do a good job that way, as well
as other details about the ink (ie. check out Eric Stollnitz's thesis
paper "Reproducing Color Images with Custom Inks").
Graeme Gill
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden