QTR-Quadtone RIP

Steve,

Thanks for sharing your insights. I like your analogy. However, I see
the change in K% occuring when converting from Gray Gamma 2.2 to QTR -
Gray Lab or QTR - Gray Matte Paper. Wouldn't these spaces be in the
2.2 gamma space? I am still not understanding this process.

Thanks for trying to provide some light on this subject.

Ken

--- In QuadtoneRIP@yahoogroups.com, "Steve Bye" <steve_bye@...> wrote:
>
> Ken,
> 
> If you are looking at the info palette it is probable that the
shadows are
> not compressed, though they appear to be. This relates to the fact
the same
> density is represented by different K% in different grayscale gamma
spaces. 
> 
> I created a grayscale step wedge in gray gamma 1.8, made a copy of
it, and
> then converted (not assigned) the copy to gray gamma 2.2 using
Edit/Convert
> to Profile. When I measure the same patch on the two different step
wedges I
> see that the K% is different. 
> 
> The issue is whether the different values of K represent different
densities
> of gray. I think they do not. 
> 
> In my example, when I measured the same grayscale patch in the two
different
> grayscale wedges, I get 96% K in the gamma 1.8 space and 92% K in
the gamma
> 2.2 space. These actually represent the same density. 96%K in a 1.8
gamma
> space is the same level of gray as 92% K in a 1.8 gamma space. (See the
> "Companding Calculator" calculator on this great website:
> http://brucelindbloom.com)
> 
> Though it is not too intuitive, an analogy is that PC monitors
calibrated to
> gamma 2.2 monitor have a darker display for the same RGB values sent
to Mac
> gamma 1.8 monitor. Since gamma 2.2 displays darker, 92% black on a
gamma 2.2
> monitor would be the same level of gray as 96% gray on a gamma 1.8
monitor. 
> 
> Seeing compressed shadows on actual prints is a different issue. If
you are
> actually converting between gray spaces instead of assigning the gray
> spaces, it seems like the prints should not have different shadows. 
> 
> Steve Bye
> 
> -----Original Message-----
> From: QuadtoneRIP@yahoogroups.com
[mailto:QuadtoneRIP@yahoogroups.com] On
> Behalf Of prof_mgt551
> Sent: Saturday, June 03, 2006 7:03 AM
> To: QuadtoneRIP@yahoogroups.com
> Subject: [QuadtoneRIP] Re: Roy's working space blocks up shadow
detail? Why
> use it?
> 
> Hi Duane,
> 
> Thanks for sharing your experience with this issue. The only gray 1.8
> that I have is gray gamma 1.8. When I convert to it from the gray
> gamma 2.2 space, the shadows are also compressed (using the info
> window in Photoshop to check the K % value). I am do not understand
> why the deep shadow steps are compressed when converting to these
> other spaces?
> 
> I can see deepest shadow detail on my screen but I loose it in the
> print unless I use the gamma slider to open up the tone curve. I would
> prefer not to do this, since I assume the response is no longer
> linear? I tried the gray matte paper profile and others for soft
> proofing and didn't see any change.
> 
> I think the basic problem is there is no software that allows you to
> softproof the QTR Printer output. Roy mentions this in his ICC
> Info.txt file, " The current version creates profiles for the printing
> side.  A soft-proofing version is coming soon."
> 
> Best wishes,
> 
> Ken
>