Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul 
Roark" <paul.roark@v...> wrote:

> 
> Frankly, I generally prefer my 1160 to hextones for matte 
printing.
> However, given the number of 1280s out there, and the 
potential of that
> machine, I've agreed to test the system (and play with it, of 
course).
> 

       One project, for example, is to see if the 1280 and
> this inkset can make good digital internegatives.  (My 1160 is 
really not up
> to the standards I want for an internegative.)
> 
> At any rate, I should have a 1280 running Eboni and Ultra Tone 
through a CFS
> in a week or so.  I'll let you know if the news is good or bad.
> 
> Paul
> http://www.PaulRoark.com
> ________________________________
> 

Hi Paul,

I've been working a lot lately transitioning from a 4 ink 1160
to a 6 ink 7500 as well as using my new QuadTone printing
software.   To make things easier I ended up using VM-Sepia in
both printers.

My first observation is that I agree that the 6 ink system seems
a fair more difficult to deal with than the 4 ink one.  I'm just
barely able to get the 7500 to be as dotless as the 1160.
A guy trying my system with a 1280 had lots of the same
problems.  

I did some Q-tip swab tests of the various inks and I'm
beginning to think that the light inks are way too dark for
what the driver software is expecting.  The swab tests give:
K=161, C=142, c=129, M=59, m=58, Y=63.   These tests
aren't real accurate but illustrate the issue.  Curiously the
two M's (the sepia toner) have almost the same density but
vary in color quite a bit:  M is a reddish orange, m is a much
browner and less color saturated.

I then tried printing out 21steps off only C and only M with
both the Epson driver and with the gimp-print driver.  The
Epson driver is somewhat tolerant of these densities but 
for cyan steps I get 100%=83 and 50%=59 and for magenta
I get 100%=59 and 50%=49  so most of the ramp up 
happens in the first 50% and its pretty flat above that.

With gimp-print things are quite a lot worse,  its very
intolerant of wrong densities, making a steep beginning
up to 50% and variations after that both up and down.  But,
seeing how I have the source code I was able to reset the
assumed densities in the software.  After this I was able to
get great step wedges -- smooth from 0 to 100%.

So I don't where this should all lead.  Changing ink formulas
would obviously be a big hassle for all the existing curves.
I'm thinking of remixing a lighter light cyan for my next load
of the cartridges but I'm doing my own curves.

Roy