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Re: [QuadtoneRIP] Re: Ink limit low limit

2015-01-28 by sanking@...

May I quote a discussion about making negatives, dithering, etc..I had with Roy early last year; he said:
"Each ink has a different dithering placement of drops. So it's best to have both more individual ink and more different inks for more hiding of the drops."
This is rather comforting about any pattern accentuation, each channel is not supposed to use the same pattern.
But making the curves "not totally congruent" may be safer anyway.
Different ink limits for each channel could maybe also help in that direction, and also attenuate the larger dots transition, if some is actually taking place?

For digital negatives I am almost certain that you want more nozzles shooting out drops. In my experience digital negatives made with only PK definitely print less smooth than negatives made with PK, Y and LLK, and negatives made with six shades of PK print even smoother.

I adjusted the K8-12 profile for the 7800 so that there are eight different curves, but total ink is the same, and printed a step wedge negative on Pictorico, with a continuous tone strip. I examined the this to a previous step wedge and tonal strip printed with a single curve, and see no difference in smoothness, or in transition. I will need to make an actual print in carbon to be certain, but from what I am seeing at this point the negatives are virtually identical.

For the record, I print digital negatives with the 7800 at 2880 dpi, Uni-Directional, and without advanced dithering options. The profile I am printing is about equal in smoothness to one I previously made with five different shades of gray, with overlapping curves. With the 7800 the smoothness is about what you would get in printing a 4X5 negative at 16X20. With the R3000 there is greater smoothness. The only absolute I can make is that 1.5 picoliter printers make smoother digital negatives than those that spurt out 3.5 picoliter drops. This is clearly evident in examining both the negatives made from these printers, and the prints themselves.


Sandy

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