Digital BW, The Print

Marketa,

You wrote:

>I just got the MIS VM inks for my Epson 1200 and am trying to figure out
>general guidelines on how to adjust the curves for my system.

I assume you have started out with the pre-made curves for the specific
printer and computer (PC or Mac) that you have.  If not get those curves
(free) from MIS or me.

>...blue ink is increased by adding more magenta,
>midtones by adding more cyan and light tones by adding
>more yellow at the appropriate place on the curve.

Yes, that is basically it.  Adding toner will also increase the density at
that spot as well as make the tone cooler.

>... what's the best way to compensate with other
>inks when you change the proportion of one ink.

The cold toner is just a hair darker than the yellow ink.  So, where you
move the toner x units in one direction, compensate by moving the yellow ink
(blue curve) x units in opposite direction.

> For example, I wanted a warmer print in the midtones
>so I increased green, but as a result that area
>of the wedge also became lighter. Should I add more cyan

For a warmer print, I assume you moved the green curve (magenta-position
ink, and thus the toner in a 6-ink printer) toward the lighter end of the
axis.  That is, you would want less of the toner ink.

Note, the curves graph can use either the 0% - 100% ink percentages or the
0 - 255 8-bit luminance scale.  One switches methods/scales by  clicking on
the double arrow in the horizontal axis.

I use the 0 - 255 scale because it gives you more control. With this scale
the darkest point is the bottom left corner of the graph.  This is point
(0,0).

So, on this axis, to increase warm, one needs to decrease the cold toner.
Thus move the green curve (magenta ink) up, toward the lighter end of the
vertical axis.

To compensate for less toner ink, move the corresponding point of the blue
curve (yellow/light gray) ink down to add more ink.

>or should I modify the transfer function

No, I would not touch the Transfer Function in this case.  Use the curves
and be sure to save the new curve with a different name.

Good luck.  I'm glad to see people getting in there and learning these
controls.  You can really custom design the look to what you want.

Paul
http://www.PaulRoark.com