Digital BW, The Print

Having mostly (don't get me started) enjoyed using the Piezography 
driver on my trusty G4 and  humble 1160, I thought my prayers were 
answered when an affordable used 7000 materialized last month. Hah!

The Piezo plugin doesn't work with the large format "Pro" Epsons. For 
a while, ConeTech sold the Piezography24 RIP for these machines, 
Windows only, for around $2K if I recall. So I get a cheap Wintel box 
and I'd be in business for a mere $2500 or so. Except do to the legal 
snafu, the RIP is no longer available from ConeTech. It is from R9, 
who don't even have a website (who are these guys?) for $1500, still 
Windows. Did I just save $500? No.

ConeTech is now touting Imageprint 5 for the big printers, $1500. 
Windows version recommended, the Mac version is "balky". OS X version 
in the works, but not even clear that quad black printing will be 
supported by IP in the future. A friend has IP5 on his 7000 using MIS 
FSN inks, very impressive results, but I will wait. I need to run OS 
X because the school I teach at will convert next year. And even the 
Piezo driver won't work on OS X.

Meanwhile, I stumble across Gimp Print, a free, open 
source/unix-based universal print driver for Mac OS X 10.2. Free? 
This I have to try. Which I did yesterday and today, and I may well 
have just saved $1500.

Gimp Print is not really a RIP, but it does allow a lot more control 
than you get with either the Epson or Piezo drivers. Installation 
(along with the companion Postscript helper ap) was straightforward 
and uneventful. Configuring printers is also a snap, but install the 
Epson driver first if there is one (I did this for my 1160 and 1200). 
In setting the printer up for Gimp Print, you can rename the printers 
and retain both driver options. The nozzle check/alignment utility is 
not accessible through Gimp Print, but ends up readily available from 
the Applications folder. Since there is no OS X Epson driver for the 
7000 yet, I'll have to get its utility via Classic.

I first tried Gimp Print with my 1200 and Gen4 color inks. It was at 
least as good as what I got through the Epson driver, but the 
ConeTech canned HPR profile still needed some tweaking. I'll play 
some more with it later.

The Selenium Tone/Museum Black carts for the 7000 are still 
back-ordered from IJM, so I set about figuring how to do quad black 
printing using the 1160 and the PiezoTone Warm neutral inks in the 
CIS. I used the standard Piezo 21-step ramp for my tests, as I know 
what it should look like (even if it often doesn't). There are many 
settings options available in GP, and some of the defaults (like 360 
dpi) are of no use. Most of what I started with changed. Making it 
work took about 20 sheets of EAM and a half dozen of HPR over about 6 
hours. As neither paper is a choice in GP, I started with the PLPP 
profile. It's an iterative process, and I made my share of mistakes. 
There are probably other ways to accomplish the same goal.

There actually is a "Quad Ink" choice, but that clearly needed 
serious profiling within each tone band-something else for later. You 
can, however, print grayscale very nicely with the default settings 
and quad inks. Dotty, yes, but quick and serviceable.

The real trick, though, is to convert the grayscale image to CMYK, 
and adjust the stepwedge tonalities with a combination of PS curves 
and Gimp's ink adjustments. This is easy to do because the Epson 
driver (which expects an RGB version of the file) is not used. 
Avoiding the Epson driver is part of the reason people buy RIPs, of 
course.

I began by adjusting the highlights using the yellow and magenta 
position inks, aggressively in the 10-0% range, and maxing out at 
about the 50% step. I ran both overlapping the range, as the "yellow" 
cools the magenta position ink a bit and adds some density. For 
whatever reason, my "magenta" ink prints light in both Piezo and 
Gimp. I also bumped the "magenta" level in Gimp Prints "Expert" 
settings to 2.0 from the default of 1.0. Yowzah, the highlights were 
smooth and dot-free, just like Piezo.

I then cut the black way back, hoping to get the kind of shadow 
separation I like in Piezo.  It was then a matter of bringing in the 
cyan to match the magenta/yellow at 50% and the black at about 95%. 
This was harder than I expected, with all the Epson paper profiles. I 
kept getting the same blocked up shadows I've seen with the Epson 
driver. As Epson has part-funded the Gimp project, I suspect they 
supplied the profiles. There was just one odd profile on the list: 
"Ilford Heavy Paper", whatever that is. Well, whatever that is, that 
was it. Bingo, shazaam, it works! Damn thing looks just like 
Piezography: dot-free highlights, smooth transitions, open shadows.

Next step was to try the half-dozen or so dither choices available in 
Gimp-Print. I got the smoothest results with "Ordered", but the 
results might be different on other printers. At least there is a 
choice.

Finally, I recorded an action in PS to convert a grayscale file to 
CMYK, add the tone curve, and send to the printer. Hardly more 
difficult than exporting to Piezo.

The curves aren't finalized yet-I may have to make some major changes 
for the six ink Selenium Tone inks and the 7000. Happy to share them 
as is with anyone looking for an OS X solution and willing to explore 
Gimp Print on their own-I can't offer any tech support:-)

Bruce


-- 
Bruce C. Kinch
Associate Professor of Photography
The Art Institute of Boston at Lesley University