QTR-Quadtone RIP

--- In QuadtoneRIP@yahoogroups.com, Howard Shaw <glassman@...> wrote:
> The black boost setting should not be changed after you have applied 
> the linearisation. If you do so the curve will need to be 
> re-linearised.

Thanks for responding.  I feel like just another noob asking the same
old questions, but it's not for want of reading the pdf help files
over and over, and searching these archives.  If anyone is working on
the documentation, I will have some suggestions about areas where it
can be made clearer, particularly in relation to sequencing.
 
> The darker than expected shadows in your print may simply be the 
> result of applying the icc profile. Have a look at this message from
> Roy:
> 
> http://tech.groups.yahoo.com/group/QuadtoneRIP/message/4497
> (about half way down the page).
> 
> When a typical icc profile for matte paper is applied the the whole 
> image becomes a little darker and the shadows end up being 
> compressed. Watch the histogram in photoshop as you apply the 
> profile.

Yes, I realise that the numbers in the file will change when you
convert to a different profile.  That's the point of converting, not
assigning.  The issue in this instance is why they change the way they
do ...

I thought that there was a fair bit of confusion in the post you
quoted.  I assume that the comment of Roy's that you were referring to
was the following:

  "When you print on matte paper there's a mapping of dMin's and 
  dMax's from the file to the paper. In general you lose more at the 
  shadow/dMax end. So with straight QTR profiles this will usually 
  mean a lighter print because the straight-line pushes the whole 
  range lighter. The idea of Color Management is to do a mapping that 
  better (but not perfectly) matches our perception. This sacrifices 
  some of the shadow separation in favor of midrange density."

My version: prints on matte papers with a linearised curve will tend
to be lighter because of the characteristics of the paper.  So we have
to use the ICC profile to push the shadow end to be darker in order to
maintain a perceptual match between print and screen, and this will
cause some loss of some shadow detail.  

I'm going to have to think some more about this.  There are issues of
rendering intent and soft-proofing to consider

F_P