QTR-Quadtone RIP

--- In QuadtoneRIP@yahoogroups.com, "milogiacomorambaldi47" 
<milogiacomorambaldi47@...> wrote:
>
> Roy,
> 
> At last this makes sense.  To verify, I ran the original JPG with
> embedded Gray Gamma 2.2 through Qimage with "printer ICC" OFF, which
> theoretically should pass the GG2.2 pixels to QTR, but resized and
> sharpened by Qimage (the whole point of using Qi).
> 
> Sure enough.  That final print matches the original QTR print of the
> TIF made by PS from the JPG with embedded GG2.2 (Qimage out of the
> loop entirely)!
> 
> One other point seems worth raising.  Your gray-readme suggests
> editing in gray-lab, then printing from PS with gray-matte or
> gray-photo.  Then you say that "in Qimage only RGB profiles can be
> used".  Well, Qimage can certainly INPUT gray profiles (it was happy
> to take my test image in GG2.2, for example).  It's just unwilling to
> OUTPUT grayscale.

If you use the printing profiles the editing space is not critical.  I still use the
gray-lab for my scanned negatives since there is no "inherent" space but 
GG2.2 is a perfectly good working space too.  If you shoot digitally and the 
camera produces AdobeRGB color files GG2.2 is a good match.

Qimage only handles RGB files internally so gray files are converted to RGB
on input.  RGB versions of my ICC profiles are really still grayscale profiles
with R=G=B so that Qimage can use them.   BTW, Adobe InDesign is another
major product that does not handle grayscale -- just RGB and CMYK.

> 
> Hence, it would seem possible to edit and save from PS in gray-lab,
> input that into Qimage (which will quietly convert to RGB), output
> from Qimage to rgb-matte or rgb-photo, and then print with QTR.

Exactly right.  Conversion can be done in PS or Qimage.

> 
> I haven't tried that yet, but can you see any reason why that would
> print differently than converting into rgb-matte/photo in PS before
> running Qimage?  In other words, it shouldn't matter whether PS or
> Qimage converts from gray-lab to rgb-matte/photo, right?
> 
> Finally, I'll try printing at 1440 and 1440/super to see if they
> match rgb-matte/photo soft proofing in PS better than 2880.
> 
> I am so impressed with QTR, your responsiveness, and this forum 24
> hours after learning about QTR.  I'm paying my shareware fee tonight!

Thanks,
Roy

> 
> Michael Miller
>  
> > Hi Michael,
> > 
> > The first comment I have is that most of the profiles were made with
> 1440 dpi not
> > 2880dpi.   This can effect the overall density of the print.  You
> can use 2880 but
> > you'll probably have to adjust the Ink Limit Adj till you get it right.
> > 
> > QTR does not look at the embedded profile in the tiff file --
> whether it comes from
> > PS or Qimage.  It just uses whatever the actual gray values are. 
> However when you
> > select QTR - RGB Matte Paper in Qimage this is a conversion from the
> source profile
> > GG 2.2 to the print profile.  This means all the values are
> re-calculated.   The main
> > area of difference is the shadows so that explains why your two
> prints are different.
> > 
> > I would think that the best screen match would be to use 1440dpi (or
> super) and
> > print using Qimage and QTR - RGB Matte Paper printing profile.  
> There's not much
> > difference with soft-proofing since it's just gray.   PS does allow
> a soft-proof with
> > Simulate Ink Black which will show the lower dMax if you use the
> Matte Paper profile.
> > 
> > Roy
> >
>