Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "koloshor"
<wiz@n...> wrote:
 
> I make a 101 square "step wedge" as part of my curve building process.
> My first negative was on Pictorico OHP film, with the printer set for
> Epson Premium Glossy Photo Paper (same way I set the 2200 and the
> 7600). The step wedge is printer with color management turned off on
> the printer driver. I'm getting a density crossover in the darkest
> parts of the negative, from 75% to 100%. The curve increases in
> density, properly, from 0% to 70% black. At 75%, it levels off, at
> 80%, density decreases until it's back to the same level it was at
> 70%, then it begins increaseing from 85% to 100%.

Let me add a couple of things:

First, it is definitely the way the Epson 4000 is dealing with black
generation. I'm used to making digital negatives on the Epson 2200,
7600, and several other machines. I've built curves for a lot of
different silver and alternative process (Pt, Pt/Pd, gum, cyanotype,
Azo). The 4000 is an entirely different animal.

It appears to have a lot to do with differences between the reflective
and transmissive density of the Epson PK, light black, and whatever
colors are mixed in by the Epson drivers.

The crossover problem extends to every paper type that I've tried, so far.

I'm beginning to think that the answer is a RIP. Has anyone ever made
digital negatives using one? Our experiments with QTR show that the
dither pattern is just too obvious for digital negatives. Our Onyx RIP
also has an ugly dither. Has anyone tried ImagePrint on digital negatives?

Thanks for any help.

Joe