QTR-Quadtone RIP

On 06/12/2012 04:49 AM, Terry Ritz wrote:
> On 12-06-07 10:47 PM, "Roy Harrington" <roy@...
> <mailto:roy%40harrington.com>> wrote:
>
>  > Finally there's the reading of the target. I think you get a lot of
>  > benefit from averaging
>  > multiple patches (more important than more steps).
>
> Roy, are you talking about taking readings from multiple prints of the
> target, or about reading a single target print multiple times (or both)?
>
> Terry.

There could be two reasons for multiple measurements of the same 
density. The printer can be less consistent so you print more of the 
same patches to measure. The measuring can be inconsistent and measuring 
the same densities several times + averaging reduces the faults. The 
21x4 target covers both. If both printer and measuring are consistent 
(for example measuring per patch) then there will be little gain by 
printing more patches and measuring them more times. With my old Epson 
9000 custom quad printer + Spectrocam I used to measure strips of 
targets that were placed in different directions on the sheet.

Today with the Z3200 or the customised K5400 + an Eye 1 Pro, I use one 
21 step target and reading per patch. The Z3200 calibration target has 
16+1 patches for each channel and is measured automatically patch for 
patch by the Z3200 integrated spectrometer, the black patches etc are 
measured longer to give a better measurement. The QTR linearisation I 
put on top is based on the 21 step target but I think that the 34 step 
linearisation may improve on that. The same for the K5400 quad or 
tritone (gloss) that has ACV curves for partitioning.

Finished the 16-bit 34 step target some days ago, will put it into 
practice at the end of the week I hope. I will then add it to the 
targets for download on my site. Thank you Roy for the instructions, I 
used another 16-bit route first that was accurate too but this one is 
faster.


-- 
Met vriendelijke groet, Ernst

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