[argyllcms] Re: Changing "ink density" in Epson driver prior to profiling
- From: BC Rider <bcrider99@xxxxxxxxxxx>
- To: "argyllcms@xxxxxxxxxxxxx" <argyllcms@xxxxxxxxxxxxx>
- Date: Tue, 19 Nov 2013 16:11:28 -0800
> For the QuadTone RIP I made some greyscale targets that show detail loss
> at more spots along the tone range. Can be used for a normal driver too.
All very interesting.
Last night I printed test charts at 0%, 20% and 40% ink density using the
Onsight image Alan mentioned. Visually, the 20% had more contrast with
stronger colors, the 40% even more so. Placed beside the 40% print the
original 0% print looked washed out.
The 0% and 20% had none of the problems or issues we have been discussing,
both were perfectly fine. The 40% has some very slight mottling in a couple
spots of deep black.
Black Dmax went from L* 5.2 down to L* 2.7 and then further to L* 2.6 with the
40% version. The grey steps were all visible except in the 40% where I
couldn't separate the last two steps.
Note: after 24 hours the ink seems to have settled at 4.9 and 2.9 and 2.9
respectively. Contrary to what X-rite claims with their Munki software, 10
minutes is *NOT* sufficient time to allow for inks to stabilize!
This morning I printed again, this time with the test target Ernst was kind
enough to share. All lines were visible in all patches for all three prints
(0, 20, 40% ink density). No apparent lost of sharpness or resolution.
Eventually I will make profiles for the 0% and 20% ink density and compare.
But at this point it looks like the +20% is a winner from this set. Perhaps a
lesser increase will provide most of the benefit. More testing is needed.
Since the patches on the left side are becoming more vibrant, I don't think the
ink changes are due to gamma. One wonders what the media type selections
really do vis-à-vis the ink density setting. I could find nothing describing
Epson drivers in this regard.
In any case, based on these test, optimizing the media and ink settings in the
RGB driver should be the first step in the printer profiling process!
Unfortunately it seems to be a lot of printing and subjective "eyeballing" for
RGB drivers. There are a lot of possible combinations of media type and ink
density. It would be nice to automate and quantify this process somehow!
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