Digital BW, The Print

Thank, Paul. You gave me the information I needed. 

--- In DigitalBlackandWhiteThePrint@y..., "Paul Roark" 
<paul.roark@v...> wrote:
> Chris,
> 
> You asked:
> 
> >Which RGB curves correspond to which VM inks? I assume that the RGB
> >curve corresponds to black.
> 
> The ink positions are different on the 4 and 6-ink printers.
> 
> On a quad printer (1160 & 3000), the dark gray ink is in the cyan 
ink
> position and is controlled by the "Red" curve.  The light gray ink 
is in the
> magenta position and is controlled by the "Green" curve.  The toner 
is in
> the yellow position and is controlled by the "Blue" curve.
> 
> On a hex printer (1200, 1280 ...) the toner is in the magenta 
position and
> the light gray is in the yellow position.
> 
> The black ink is controlled by the Epson driver looking at how much 
of the
> other inks are being poured in.  If, for example, two of the inks 
are almost
> 100% on, the driver will start adding black ink when the third 
color is
> about 1/3 on.  So, as a practical matter, you have indirect control 
of the
> black ink, but you do not have a specific curve that directly 
controls that
> jet.  (The CYMK mode does not help, either.  A true RIP would give 
this
> control.)
> 
> The RGB curve changes the colors together.  So, it is very useful 
to match
> the print to your screen or make corrections in, for example, the 
top or
> bottom of the range when the other curves already have the maximum 
number of
> point they can handle (15, I think).  You may notice that I've 
squeezed in
> some points on some of these curves up in the 0% - 5% range when 
there was a
> poor ink distribution with the other curves.
> 
> Paul
> http://www.PaulRoark.com