Hi :) Graeme Gill wrote:
Hmm. As far as I can tell the auto aim values are for 100% colorant for your file (ie. if you do a plot with -p, all the crosses are at 1.0), since your device response is already pretty linear, and doesn't fall over very much near 100%.
Ah, I've misread / misunderstood the meanings of the fields in the .cal file, then - I was thinking the DELMAX_AIM values were the suggested ink limit. Oddly enough for CMY and K they're fairly close to the per-channel ink limits GPLin suggests - the coincidence was confusing me!
The device response of that .ti3 file looks roughly linear largely because there's a significant gamma adjustment being applied between the targen-created testchart and the printer - (a) to avoid using absurd amounts of ink, and (b) to better distribute the test patches.
(Any chance of a future version of targen being able to generate gamma-adjusted step wedges, by the way?)
[If you look at the .cal then DEVMAX_USED is 1.0 for all the inks.]
Yup, I see that. So I take it the auto-aim doesn't attempt to use the hue-shifts at colorant saturation to decide where to stop?
I tried applying the gamma adjustment to the device input values in the .ti3 file, and the five colorants still get a DEVMAX_USED of 100%, and black gets about 50% - I shall experiment further :)
All the best, -- Alastair M. Robinson