Digital BW, The Print

Jeff,

You wrote:

>... regarding the Epson driver "turning on the black
>jet" requires a follow-up question. ...
> In general, under what circumstance does the driver
>deliver the black ink?  ...

The driver looks at the three color curves and turns on the black jet when
the three together approach the 100% black point.  In general, you'll want
the cyan (dark gray) to be close to full on when the black ink starts.  So,
to get the darkest you can without the black, have the cyan and magenta
fairly far down, then the lighter ink, indirectly, will act as a control on
the black ink.  If the two other inks are close to 100%, you'll start
getting black ink with the third ink about 1/4 or 1/3 the way down from the
top.  If it comes down at too steep an angle, you will end up with an uneven
ramp.

To use the light ink for both the indirect black ink control and the
highlights, you need that ink to go into a reverse slope in the middle of
the graph.  For this compromise, recall that straight magenta in the
highlights makes for very smooth highlights.  That is, the lightest ink is
almost irrelevant.  So, have it pour in some ink right at first, but then
pull it back up to use it for the black control.

Since you only have 15 points per color graph, you also have to
compromise -- choosing one ink to be the primary control for the part of the
graph where that ink matters the most. The cyan in the midtone ink and needs
all its points there.  Don't have any cyan in the top 25%.  The magenta is
actually the main highlight ink, except for maybe the first 5%-10%.

Hope this helps.

Paul
http://www.PaulRoark.com




Paul Roark wrote:
<snip>
> The MIS VM "warm" curve will give results that should look OK.  It
holds the
> lightest (yellow position, blue curve on the 1160) ink back the
most.  It
> then pulls it into play just enough to turn on the black jet.
<snip>