Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Ernst Dinkla <E.Dinkla@c...> 
wrote:
> Roy Harrington wrote:
> > 
> > 
> > I've added a set of the same basic Lab and Printing profiles that have
> > been changed to RGB format.   These should be used for printing 
> > using Qimage.  Set the printer output icc profile to one of the rgb profiles.
> > I'm not positive how to change the file profile to RGB Lab in Qimage but it
> > works fine in Photoshop.   
> > 
> > Note that the RGB Lab space is a true RGB space but it has a transfer function
> > with linear Luminosity rather than a Gamma transfer function.   It is not a
> > space with an L, a, & b channel.  It might be interesting to use this for color 
work.
> > 
> > Roy
> 
> Roy,
> 
> I have tried all kinds of programs with all the 6 QTR (RGB +
> Gray) profiles on XP and 2000pro and one way or another I get
> very different appearances in the menus. The profile
> installation order may have an influence. I know, there's no
> logic in that.
> 
> Done so far:
> Photoshop CS + Picture Window Pro on W2000pro, Photoshop
> Elements and Qimage on XP. Could try Photopaint 9 but that one
> isn't installed right now.
> 
> Both Picture Window Pro and Qimage are based on LCMS  open
> source but they do not behave similar.
> 
> One thing for sure is that Qimage doesn't show QTR
> RGB Lab in the color spaces choices menu on XP. However it
> appears in the monitor and printer profile choices like the
> other 5 (RGB +GRAY) profiles do. Photoshop Elements does the
> same but its black box approach defaults to Adobe RGB (in
> advanced CM mode) as the space so I can't tell whether it
> actually notices the QTR RGB Lab space profile. No chance to
> select another space AFAIK.
> 
> Had several meltdowns of Qimage, some with the message that
> lcms couldn't cope with the profile while Qimage was
> processing a print file.
> 
> The only way it seems to work is by making in PS a greyscale
> RGB file with QTR RGB Lab embedded and loading that file in
> Qimage, printing it to file with the QTR RGB Matte or Gloss
> printer profile. All dry trials as I can't run QTR right now
> with the Ultratone inks in the "wrong" ink channels. A true
> greyscale Tiff with QTR Gray Lab embedded and printed the same
> way doesn't work with the QTR RGB printer profiles. It runs
> but the processed tiff shows a lot of black..
> 
> Ernst

Hi Ernst,

I'm new to using Qimage so I don't know all the nuances of it.  
I can select any of the 6 QTR profiles in the ICC page -- i.e. input,
monitor and print as long as I select "All Windows Profiles".   If I select
any of the gray ones though whenever I use it little-cms complains
about colorspace and the program exits.  But the RGB ones seem to
be accepted except the conversion to the Matte Paper profile seems to
truncate the black end rather than do a nice smooth curve.  I don't know
if that's built into lcms or if its controlable.

Roy