QTR-Quadtone RIP

In Step 1 I should have said I start with 48-bit RGB images and that 
the softproofing monitor image of the RGB image is "toned" BW -- 
otherwise why softproof with an RGB icc profile? :)

--- In QuadtoneRIP@yahoogroups.com, "Jeff Randall" <jrandall@...> 
wrote:
>
> Joost: 
> 
> In general I also use your WF1.  But I edit with Pictrue Windows 
Pro 
> using the softproofing QTR RGB icc profiles I generated from 
> linearized QTRgui printouts of the QTR 21step wedges and a similiar 
> rendering intent as you.  
> 
> 1) In my case editing starts with 16-bit RGB images (usually in 
> AdobeRGB) that I first convert to 16-bit BW using the Picture 
Windows 
> equivalent of a channel mixer.  Conversion removes any profile 
tags.  
> [Note the softproofing monitor image of the RGB image is BW.] 
> 2) Set B/W points and use curves (combinations of RGB, HSL, and 
HSV) 
> to get the 16-bit on screen image I want.  
> 3) Resize for printing.
> 4) Sharpen as needed.
> 5) Use Neat Image to remove grain as needed.
> 6) Save the image as a 8-bit tiff image.
> 7) Print through QTRgui using the .Quad profile used to create the 
> softproofing icc profile.  
> 
> Unlike your Step 4, I don't tag or convert my images to any 
profiles 
> during my workflow--QTRgui seems to work just fine.
> 
> Jeff
> 
> 
> --- In QuadtoneRIP@yahoogroups.com, "Joost Horsten" <j.h.j.h@> 
> wrote:
> >
> > 
> > Hi all,
> > 
> > In view of the confusion we had lately on this forum on the 
> different
> > QTR workflows, I decided to do a small experiment, comparing two
> > workflows.
> > 
> > Workflow 1
> > 1) editing the image. I used both AdobeRGB and Gray Lab as 
> workspaces,
> > without differences, and (at least to my understanding) the 
editing
> > workspace is of NO relevance here. Any workspace will do
> > 
> > 2) softproofing the image with the gray-matte-paper icc profile
> > (setting: "preserve numbers"=OFF, "rendering intent"="relative
> > colorimatric", "blank point compensation"=ON, "simulate black 
> ink"=ON)
> > 
> > 3) flatten, convert to 8-bit grayscale
> > 
> > 4) convert profile to "gray-lab" and save as tif
> > 
> > 5) print the image with QTRGUI
> > 
> > Workflow 2
> > 1) editing:  same as workflow 1
> > 
> > 2) NO softproofing
> > 
> > 3) flatten, convert to 8-bit grayscale, smae as workflow 1
> > 
> > 4) convert profile to "gray-matte-paper" and save as tif
> > 
> > 5) print the image with QTRGUI, same as workflow 1
> > 
> > 
> > The hypothesis for this experiment was that these workflows, 
> although
> > different, are actually equivalent.
> > 
> >   It's hard to get the hard physical, quantitative evidence from 
the
> > results.  It would involve direct comparison of screen luminances 
> with
> > print luminances and  I do have a spectrometer but I have 
currently 
> no
> > idea how to directly compare emissive and reflective values.
> > 
> > Nevertheless a qualitative comparison DOES support the 
hypothesis. 
> In WF
> > 1, the softproofing lightens  the image, with respect to the 
> original
> > image. So if ones edits with Softproofing "on", the actual image 
is 
> a
> > bit darker. In WF2, the conversion of the image the gray-matte-
> paper,
> > darkens the image. This is NOT visible on the screen, since 
> photoshop
> > compensates for this, but it can be checked with the eye-dropper: 
> the
> > LAB values drop (or the K-values increase which is the same) after
> > conversion.
> > 
> > So in BOTH cases  a darker image is sent to the printer than the 
one
> > displayed on the screen.  My explanation is as follows:  the 
dynamic
> > range/contrast of paper is lower than that of a screen. Paper can
> > typically display L-values between 15 and 95.  So, especially in 
the
> > blacks there is quite some descrepancy between paper black and 
image
> > black.  Both WF1 and WF2 are ways to compensate for this. WF1 
uses 
> the
> > gray-matte-profile to compensate the screen-paper difference on 
the
> > screen, while WF2 compensates it in the printer.
> > 
> > WF2 is the workflow as advocated by Roy, WF1 is the one I (and 
some
> > others) use. But now my (preliminary, since based on incomplete
> > evidence) conclusion is that they lead to the same result. I 
> personally
> > always could live better with the theoretical foundation of  WF1, 
> but
> > now I think I understand that it's just a matter of taste.
> > 
> > Open for any comment and critique. For the ones more 
knowledgeable 
> than
> > I: please check if I used the right settings for softproofing.
> > 
> > Joost
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > [Non-text portions of this message have been removed]
> >
>