QTR-Quadtone RIP

Correction - It is available on the Mac version of Photoshop CS5.

That being said, would it be best then to do all work in that setting ? 

--- In QuadtoneRIP@yahoogroups.com, "kenleegallery" <kenlee333@...> wrote:
>
> You're right: my image was (accidentally) in Dot Gain 20%.
> 
> You mention Generic Gray Gamma 2.2, which seems rather important on the
> Mac if we have a recent version of Photoshop and OS X 10.6 or higher. 
> In a previous discussion http://www.dpug.org/forums/sitemap/t-2255.html
> <http://www.dpug.org/forums/sitemap/t-2255.html%20> , Harlan said this
> (emphasis mine):
> 
> "Roy Harrington noted that whatever gray space you use in CS5 and OS
> 10.6 that, on printing, it getsconverted into the "generic GG 2.2"
> space. So unless your default gray space in CS5 is this one you will
> have trouble onprinting.  The consequence for me was that my digital
> negatives would plateau in the finaltwo steps causing blocked highlights
> in my prints. Working in GG 2.2 I tested adozen modified QTR profiles
> and many gray curves, getting more and moreextreme, to try to get rid of
> this plateau without success. Wasted nearly aweek of darkroom time and a
> lot of palladium. I thought it was due to somequirk in the spectrum of
> my new light bulb in my Nuarc....
> I see the take-home message as to either print in CS3 or work in CS5 in
> the"generic gg 2.2" space that your print ends up in anyway
> (haven'ttried that yet but plan to). From my experience it could be
> really tough tore-calibrate for printing in CS5 without the gray space
> coordination workingfor you."
> 
> Can we create images in Generic Gray Gamma ? Or rather, can we assign or
> attach that profile  to a Grayscale image ? Perhaps I'm missing
> something, but I don't see it as a choice on my copy of CS5.
> 
> Noting that sRGB is compatible, would it be wiser (for QTR purposes) to
> work in that color space, even though the image is 16-bit grayscale ?
> Another advantage is that the same image could be presented on the web
> directly.
> 
> Thanks !!
> 
> (I've been trying to make a Pt/Pd profile - working in Gray Gamma 2.2 -
> and finding it hard to get paper white without blowing the high values.
> With so many variables in the process, I can't help but wonder if this
> is one of the areas I have overlooked)
> 
> --- In QuadtoneRIP@yahoogroups.com, Roy Harrington <roy@> wrote:
> >
> > Ken,
> >
> > Using the Photoshop eye drop sampler has a lot more to it than one
> > would think.  In general if you "look"
> > at values that are the same format as the file you see the actual
> > values in the file (or a simple calculation).
> > In other works for an RGB file if you look at R G B values you do see
> > what's in the file.  For a grayscale
> > file, K values are a simple calculation.  (internally 8-bit files are
> > 0=black to 255=white, 16-bit files are
> > 0=black to 32768=white).  K = (255-value)*100/255.   This is pretty
> > simple and probably what you already
> > expected.   But whenever you look at values other than the same format
> > the calculation go though
> > color management.  This means that the embedded profile (if one) and
> > the settings under Color Settings...
> > are all involved in what the eyedropper reports.  For instance if you
> > look at R G B with a grayscale file
> > you see the icc conversion of the internal gray value from the
> > embedded profile (or working gray if its untagged)
> > to the working RGB profile.  It may appear that you a looking at the
> > internal 8-bit values but you are not.
> >
> > I'm not very familiar with using HSB but like LAB you are seeing the
> > conversion from the grayscale profile
> > to those values.   So the reason you are seeing those B values is
> > because that's the "definition" of the
> > profile that is being used.  BTW, I thought I try this in PS and the B
> > values you mention actually
> > correspond to Dot Gain 20% not Gray Gamma 2.2 -- check out your file
> > and Color Settings...
> >
> > That's the long answer -- the short answer is: for step wedge stuff
> > don't look at HSB or LAB or anything
> > but K values.   Stepwedge files are meant to be artificial -- exact
> > values that you want to send to the
> > driver, you don't want any color management involved.   The posterize
> > command that you probably
> > used is also completely profile ignorant so that's just fine for
> wedges.
> >
> > --
> >
> > This seems like a good place to mention -- the K vs R G B eyedropper
> > stuff is worth understanding
> > but its often annoying nevertheless.  So one thing that makes this
> > less of a problem is to pick
> > grayscale and RGB working profiles that are "compatible" i.e. have the
> > same gamma structure.
> > This makes the conversions "look" like you expected.
> >
> > The most common pairs are:
> >   Gray Gamma 2.2 and AdobeRGB
> >   Generic Gray Gamma 2.2 and sRGB
> >   Gray Gamma 1.8 and ProPhotoRGB
> > (note that Gray Gamma 2.2 and Generic Gray Gamma 2.2 are distinctly
> different)
> >
> > Roy
> >
> >
> > On Tue, Jan 17, 2012 at 9:28 AM, kenleegallery kenlee333@ wrote:
> > > Let's say we make a new image in 16-bit grayscale with a Gamma 2.2
> profile, and create a step-wedge with 11 steps. We get an image whose K
> values go 0, 10, 20... 100. Fine.
> > >
> > > However, if we mouse over the other patches, we see some
> discrepancies between the K value and the HSB B value. For example, the
> middle patch shows a K value of 50%, but the B value is 58%. Similarly,
> where K = 10%, B = 92%.
> > >
> > > Why aren't these two measures simply the compliment of one another ?
> > >
> > > Which system is appropriate for making a step wedge, when
> calibrating with QTR ?
> > >
> > >
> > >
> > > ------------------------------------
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> >
> >
> >
> > --
> > Roy Harrington
> > roy@
> > www.harrington.com
> >
> 
> 
> 
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>