Andrej Javoršek wrote:
Hello!Fine, having a huge set of measured test patches for verification is a good idea.
I would like to get comment on my approach to get the smallest possible (but still useful) patch amount for
quick profiling of news print offset press. My motivation is to be able to profile press with small amount of
patches that can be printed during normal press run (without need for common test-chart print run).
Patches should be printed in border (cut off) area of paper so probably I could only print some 50 to 100 patches.
The approach I'm considering is to first (and only once) print really big test chart (4000 to 5000 patches) and measure it.
After that I could use "splitcgats" to get fraction of those measurements, create profile with that fraction and use "profcheck" against the whole set to get dE for that set. I can repeat "splitcgats" 500 or 1000 times to get statistically good representation. I could repeat same test for 2 or maybe 3 different papers to se if patch set is more or less the same for them.
* Create N patches with targen (where N is the number of desired patches, 50..100 as you said), using the same options you would use to generate the 50..100 test patches intended for being printed on the border * For each patch generated by targen, find the closest patch in your large set (minimum euclidian distance in CMYK space), and add the found patch from the large set to the .ti3 file which you use to create the N-patch profile. * Then create the profile and verify against the huge test set
I have the ability to use Xgrid consisting of 20+ IMac's so the speed is not the main concern.
The script I would feed to the grid is something like that..
#!/bin/bash number=$1 cgatsin=$2 cgatsout=$3 splitcgats -n25 -r $number "$cgatsin" "$cgatsout$number.ti3" /dev/null profile -qm -B "$cgatsout$number" profcheck -k "$cgatsin" "$cgatsout$number.icc"
than I could call that script arbitrary number of times with changing parameter of $number (eg. from 1 to 1000).
- Does this sound as reasonable solution?
- Is using integer as -r parameter in "splitcgats" good thing to do or is better not to include parameter at all?
- Is quality medium good in "profile" for that purpose or could I use low?
- Is using dE2000 in my case really better than using dE76?
- Please reconsider and advice!
Best Regards Andrej Javorsek