Can anybody please point me to guidance on ink limiting workflow?
I’m testing with various white matte papers and I’ve started to run into issues on the thinner end of things (110gsm ish) where papers are warping and losing their flatness due to the ink load.
I can see that there are ink limiting functions in both QTR settings and in piezography pro excel sheet. But I haven’t been able to find out anything about the difference in application or effect of them, nor any workflow examples. There is brief mention in the PPE v2 manual of Variable Ink Limiting and a teaser to a video and full tutorial coming soon.
I am guessing that limiting ink will interact with curve creation as one iterates through, but I can’t think how. Is it done for every curve iteration and if so are different values set every time? Or is it done only once? For example, from the manual it is explained that channel curve smoothing is something to be applied on the initial new curve and is then is baked in such that no smoothing need be applied to subsequent iterations of that curve.
I have tried limiting ink in QTR by -10%, -20%, -30%,-40% increments. The paper starts to keep its shape/flatness around the minus 30-40% mark, however by this stage the print is losing a lot of its ‘punch’ as it were. I was about to start messing around with the QTR ink limit calibration worklfow but then noticed the PPE v2 manual warns against getting into old QTR workflows.
Help much appreciated.
My set up is Mac OS X 11.7.3 // Print Tool 2.3.4 // QTR 2.8.2 // Epson 3880 Piezography Pro installed.
These curves were made by loading a hahnemuhle photo rag curve into the starting curve, deleting the measurements entirely, and then going to the limiter and limiting everything down to 50% except for the darkest tones which were kept at 100%. That is a different way of limiting ink that with QTR which limits the darkest tone as well.
Then a target was printed with these new limited curves and then the curves were linearized.
Basically if you print a target and see the pooling/rippling in certain tonal areas you can load that curve into the tool and limit those specific tonal areas DOWN. Then you linearize.
I have been working from the uncoated master curves to begin with, though I didn’t know they were already ink limited.
So would something like the following be right as a way to get to the ideal ink limits for a particular paper?
print initial target, “target_init”, using uncoated master curve
visually inspect “target_init” for signs of pooling/rippling
limit ink for affected tones
measure “target_init” and copy paste into measurements tab
copy paste master curve into starting curve tab
make smoothing adjustments
copy paste new curve tab into new quad file, “ltd_curve_1”
print new target, “target_1”, using “ltd_curve_1”
visually inspect “target_1” for signs of pooling/rippling
repeat steps 3-9 until the ideal ink limits are found to print a “target_N”, from “ltd_curve_N”, that shows no signs of pooling/rippling
measure “target_N” and copy paste into measurements tab
copy paste “ltd_curve_N” into starting curve tab
make smoothing adjustments, return all ink limits back to 100%
copy paste new curve tab into new quad file, “ideal_ltd_curve_1”
carry on iterating through linearisations to heart’s content knowing that correct ink limits for paper are now baked in and can be left at 100% from “ideal_ltd_curve_1” onwards
Hi Walker, apologies, I’m sure you have your hands full - I’m still a bit stuck/not sure I’m adjusting the ink limits correctly. What did you think to my approach above? Many thanks, Chris.