QTR-Quadtone RIP

--- In QuadtoneRIP@yahoogroups.com, "Roy Harrington" <roy@...> wrote:
> 
> 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.

To recap, running the highly tweaked GG2.2 test image (8-bit JPG)
straight to QTR works great.  Running the GG2.2 image through Qimage
(converting to QTR-RGB-Matte) to QTR blocks up the shadows.  Running
the GG2.2 image through Qimage (with no ICC conversion) to QTR works
great.

So... trying to move toward editing with a standard working space of
QTR-GrayLab and printing with QTR-RGB-Matte, I loaded the GG2.2 image
into PS, *converted* (not assigned) it to QTR-GrayLab, and saved it. 
Running that through Qimage (converting to QTR-RGB-Matte) to QTR
blocks up the shadows again!

What's happening?  Is it simply not possible accurately to convert
from GG2.2 to QTR-GrayLab on a highly tweaked 8-bit image?  The
histogram certainly changed shape somewhat.  Might this have worked if
the GG2.2 image were 16-bit?

If not, then I'm still confused.  Otherwise, then perhaps there's hope
for my previous workflow, which begins with Canon RAW files, then
Adobe Camera Raw, then 16-bit ProPhotoRGB, etc.  I'm hoping that
converting to QTR-GrayLab early in the process, editing entirely in
16-bit, converting to 8-bit only when all is ready, then converting to
QTR-RGB-Matte with Qimage, and finally printing with QTR... will do
the trick.  Sound plausible?

Michael