Digital BW, The Print

> Why not a flatbed printer, say 3x4 feet, with 2 sets of separate 6 color
> heads. The paper would be vacuum held to the bed. One set of heads would
> make a pass and drop the CMYKLcLm the second head would follow and drop the
> next 6 colors. Engineers are smart enough to build such printers now, the
> alignment of the two set of heads can already be done. The software side of
> it may be a bit of a challange. After reading Dan's post that may also be
> relative simple. The big thing would be the cost. You are not going to be
> able to buy this printer for $5000.00
> 
> Jim Davis

Back when I thought I might be able to get reasonable registration between
two 3000 printers I filled one 3000 with MIS CMYK inks and another with MIS
light cyan and light magenta with the remaining two channels reserved for a
blue and violet whenever they should appear.  I found I could make a profile
based on running the target file the same way I ran the print - make a spot
bump channel for the light cyan and light magenta and suppress the regular
cyan and regular magenta in the highlights.  But that was in Photoshop 5
days and I needed to do it with two profiles and a curve - one profile to
convert the RGB to standard printer RGB space and the other (a faux CMYK
profile) to preview the file as I applied the curve that suppressed the
highlights while I turned on the bump spot channels.  In other words it was
a pain in the rump but showed promise, even with the RGB driver.  But the
lack of registration between two separate 3000s was pretty much the killer
of that idea.  Really it is mostly a matter of some sort of multi-strike
printing with very good registration.  If someone made a printer like you
suggest and it didn't break the bank I'd be stuffing it with multi-hued inks
and spending all my time in experimental bliss - especially since I could
put in multiple grays as well!

Blatner and Fraser describe how to do a bump plate in Real World Photoshop
and reference a plug-in that does it automatically.  Not all that hard to do
actually - at least not hard compared to some manual quad separation methods
- but getting a way to profile and preview the combination of the regular
inks and the added inks is what becomes difficult (or at least complex and
confusing).  The spot channel controls in Photoshop only approximate the
appearance of the resulting print but if you have a large run and can tweak
the file until it prints right that might be a reasonable approach.  In
Photoshop 6 you convert to standard printer RGB space, turn on the RGB
softproof feature with the black ink simulation feature, then lay in a spot
channel and adjust its color and opacity to match a test print.

For experimenters: there is no reason that these bump plates have to be
limited to non-standard inks on a special printer.  If you can roll back a
7000 and reprint or get reasonable double strike capability with some other
printer you can bump any standard ink (including the black in quadtone
printers) by making a spot channel and turning it off on the first strike
then turning it on (and turning the main image off) on the second strike.  I
think someone posted something like that on this list about a month back -
but again, making an *accurate* previewing profile might get pretty nasty.

Dan