QTR-Quadtone RIP

--- In QuadtoneRIP@yahoogroups.com, "milogiacomorambaldi47" 
<milogiacomorambaldi47@...> wrote:
>
> Greetings, all.  I've been experimenting with QTR for my Epson 4000
> with OEM (UC, K2) inks.  I haven't (yet) acquired a densitometer or
> built custom profiles, so I'm using profiles that came with QTR.
> 
> I'm comparing an image run (nearly) directly into QTR with a version
> run through Qimage into QTR.  The Qimage print appears darker in the
> darkest 10% (based on 21-step and dark-shadow-detail image regions). 
> This was discussed in this forum in January 2005 but apparently not
> resolved.
> 
> Any new insights?  I like Qimage's resizing and print sharpening, and
> I may be able to regain QTR's native ability by fiddling with ink
> limit and gamma... but I'd rather be sure first that I'm not
> experiencing pilot error.
> 
> Thanks in advance for your consideration.
> 
> Test environment:
> 
>    - Windows XP/SP2
>    - Photoshop CS2
>    - QTR v2.4.2, Quad400, 2880 dpi, matte ink, uni-d, ordered dither
>    - QTR UC-EEnhMatte-cool (100%) UC-EEnhMatte-warm
>    - QTR ink limit = gamma = 0
>    - Qimage Studio Edition v2007.113
>    - Qimage 360 ppi, Hybrid interpolation, Sharpen 5 (default)
>    - Epson Enhanced Matte paper
>    - Northlight Images B&W Test Image (8-bit JPG, Gray Gamma 2.2)
> 
> Comparison tests:
> 
> 1.  In CS2, resize JPG to 7.07 x 10.00 inches (300 ppi).  Save as
> 8-bit TIF with embedded Gray Gamma 2.2.  Print with QTR.
> 
> 2.  In Qimage, specify page of 7.5 x 10.00 inches (360 ppi), then
> print JPG (same embedded Gray Gamma 2.2) to TIF with "QTR - RGB Matte
> Paper (P, BPC)".  Verify embedded QTR profile with CS2.  Print with QTR.
> 
> I somehow suspect that a key question is whether QTR pays any
> attention at all to the embedded profile in the incoming TIF.  Roy?
> 
> If it does not, then am I simply seeing small differences between the
> original JPG/TIF (tagged with Gray Gamma 2.2) and Qimage's TIF that it
> is color managing to (and tagging with) "QTR - RGB Matte Paper (P, BPC)"?
> 
> If so, then how should I adjust things in order to soft proof accurately?
> 
> Michael Miller
> Atlanta, GA
> (milogiacomorambaldi47 on Yahoo)
>

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