Digital BW, The Print

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

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