QTR-Quadtone RIP

On 06/04/2012 03:45 PM, Ernst Dinkla wrote:
> Is it necessary to have steps of 5% or 2% in the targets to let them
> function in the QTR linearisation and profiling tools? In other words;
> would a 33 or 34 step target with 3% increase and one 4% or 1% step
> compromise the algorithms of the tools?

No reply yet. Could be a stupid question and do not hesitate to rub that 
in then, I have written stupid questions before.

Let me explain why I wrote that question. I am looking for a compromise 
between the 21 and 51 step greyscale targets. The last can create issues 
when either the basic tone range of the printed target is too irregular 
and/or the density measurements are not increasing properly. The 21 step 
does it well on those aspects but if I create RGB curves with Photoshop 
etc the curve control points are close to the 21 number and I think that 
the linearity etc could be improved by a curve based on a higher, odd 
target number to take out interference between the two data sets.
To create an accurate, regular 8-bit target there is no other sensible 
choice than identical steps of 20+1 or 50+1 so 5%K or 2%K steps. I can 
make a 16-bit (15-bit+1 actually) target with 35+1 steps and am already 
halfway that work but if there is a bottleneck on 16 bit in either Color 
Port, Measure Tool, QTR-Create-ICC-RGB tool's linearisation, the 
application color management in printing, then that work is idle. 
Whether the driver in the end delivers 8-bit data to the printer is of 
less concern to me but up to that point I would like to have 16-bit 
processing. 16-bit driver would be nice too but is not available in all 
cases, some rounding off at that stage does not worry me.


-- 
Met vriendelijke groet, Ernst

Dinkla Grafische Techniek
Quad, pi\ufffdzografie, gicl\ufffde
www.pigment-print.com