Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "pr_roark" <pr_roark@...> wrote:

> I'm going to start with the Eboni-6 dilutions -- 30, 18, 9, 6, and 2.  The Carbon-6 dilution ratios have not worked will in K3 printers using the Epson driver due to the M and C dilutions being too far off the printer driver's assumptions.  With QTR this is not an issue, but I think there are situations where the Epson driver is needed.  


I've been working on a monotone inkset based on the HP black and C-6 base using the Eboni-6 dilution ratios.  It's running in an 1800 with Eboni for the MK and 100% Vivera Black for the PK and MIS Glop in the GO position.  The goal is a K-6 printer for both matte and glossy.  Tones so far are wonderful with papers allowing for slight variations in neutrality and I'm very happy there.  GLOP laid down with the ink deals with all the bronzing on the F type papers while RC type glossies and semi-glossies get a second coat of all GLOP via QTR and that deals with even the worst bronzing.  Qtr has been quite a challenge although workable with the rough spots in the deep shadows and unsmooth gradients.

The gradients sent me toward Paul Roark's RGB curve control/ICC work flows and there I can get silky smooth gradients but I'm running into a bit of a stump.  Inks are loaded per the 1800, around the color wheel, with the 2% dilution at Y and the  30% dilution in the Cyan position.  What I have been doing is printing a 21 step wedge (adobe rgb) with various rgb ACV curves.  The stepwedge  is printed out of CS3 with "No Color Controls"  and will get me a step wedge roughly where I need it at the 50% point.  I then apply the same ACV to the QTR "raw" file, save it, link it to the stepwedge L*a*b test printout and process it through Qtr's CREATE-ICC-RGB.  I Load the ICC and print the stepwedge out through it: (Photoshop Manages Colors, Appropriate Profile, etc.) for a final check.  What I get is a slight darkening of the stepwedge starting from about the 25% step on up when printing through the ICC.  Where I had decent separation in the stepwege printed with the curve (continuously increasing etc.) it closes up in the shadows when printing through the ICC.  I'm assuming the ICC should replicate the curve and other than a better linearity things should be relatively the same between the stepwedge printed with the curve and the stepwedge printed without the curve but through the ICC.  

I'm questioning the initial printing of the stepwedge with the curve:  No Color Control seems right to me but I may be missing something.

I also wonder if there is some unseen magic going on with the Epson driver and the use of the color inputs to control the relative ink densities.  I have been using individual RGB curves to influence light and dark areas as well as a combined RGB curve deflection starting at about 75% density to help with opening the shadows.

I'm open to any input from Curves users here.  In the meantime I'll work on the QTR approach but something tells me the gradients will just not get as smooth as they can with the Epson driver.

Thanks All.