QTR-Quadtone RIP

--- In QuadtoneRIP@yahoogroups.com, "robert49brake" <robert49brake@...> wrote:
> I can see from your readouts that the Piezography profiles/inksets are getting something I cannot duplicate with QTR and a custom inkset I'm playing with.    The inkset is Eboni Matte Black and 6 dilutions of HP Vivera Black plus glop.  The obvious goal is a dedicated b&w 8 head printer with matte and glossy capabilities.  (I've been patiently waiting for J. Cone to do all the work:)  Piezography seems to be going in another direction so I decided to play with it myself.  
> 
> The hang up on this and a previous UT-3D inkset with the 1800 has been separation in the deepest shadows and artifacts at the transition to the MK ink.  When looking at Cone's .quad files he obviously has a different method of profiling (creating the curve files) for QTR.  One obvious aspect is that he is able to overlay his individual ink curves in a way that QTR, in it's native partitioning, does not.   Everything in QTR seems to be contained in the .quad file instructions to the printer, but, how you get there seems a matter of choice.

I'm currently playing around with a R285, also a 1.5pl printer and I'm planning to play with HP Vivera dilutions as well. I've not decided yet to go for a 3K multi-purpose tonable matte-gloss setup or for a 5K or 6K setup like yourself. 

How you profile with QTR? Just straightforward all inks as gray inks? 

I was considering (but have not tried yet) an alternative approach:
- combine K , LLK and LLLLK in a QTR GRAY curve
- combine LK, LLLK (and LLLLLK if present) in a QTR TONER curve
You can easily simulate this in QTRGui. Of course, ink limits have to be reduced.

In this way you get a much larger overlap between the inks: 3 inks in the darkest area, 4 in most of the tonal range and still 2 in the highlights. This should give (much?) smoother transitions between the inks. Many comments about the Piezograhpic inks are actually about their profiles and their large overlap of inks. 

As I've still to make the dilutions so I can't try this yet, so I've no hands-on experience yet.

Any thoughts or experiences?

Joost