QTR-Quadtone RIP

Thank you for your help, I’m starting to feel like I’m on familiar ground.  I think I will install QTR on my MAC and see if it doesn’t help clear up the questions I have.





I’d like to pick up on a term both of you are using « adjustment curve ».  I’m still a little confused about distinguishing ink level adjustments from target adjustments,  both « image to image » as Richard says , and systemic, ( that can be applied blindly to all images being sent from the same work space).





In my targeting process the objective of systemic curves is, firstly, mapping the black point to maximum shadow (I don’t usually use perceptual rendering) and secondly, linearization, that is,  trying to realign the L* values  on a shorter axis. The objective of image to image targeting curves is to de-linearize the reproduction curve where certain shapes and contours of the image have been disadvantaged by a uniform compression.





Is it possible that the QTR workflow attempts to combine what I am calling systemic target adjustments with media curves?


 



Also, given what Richard said about colour managed work flows blocking up the shadows, which would be the fault of the perceptual rendering table, (the recommended rendering intent with QTR profiles).  It sounds like the QIDF is not vulnerable to this problem, at least not when used in a « same as source » work flow that avoids colour management. I’m still unclear as to how an ICC workflow with a colorimetric conversion using perceptual rendering (which, AFAIK cannot be neutral, it must remap black and compress all grey values even if there is no black in the file.)  can produce the same results as a « same as source » work flow even if that curve was used in the production of the ICC profile.





How does it escape the perceptual rendering table moving tones around after they have been perfectly aligned?





Eugene








De : QuadtoneRIP@yahoogroups.com [mailto:QuadtoneRIP@yahoogroups.com]
Envoyé : July-27-16 1:31 PM
À : QuadtoneRIP@yahoogroups.com
Objet : [QuadtoneRIP] Re: QIDF versus ICC









I just reread the part where you would you could do all this on a Mac instead of Windows. I know Paul likes the QTRgui, but once you get used to entering the inputs into a text file you will wonder why you ever used the windows version. The biggest advantage is being able to use PrintTool on OS X/macOS.





RB