Digital BW, The Print

Bruce,

> ...Please correct me if I'm wrong here:
> 
> The UT7 inkset appears to have two toner sets - three cool (cyan) inks
> and three warm (magenta) inks with a common black. Basically two
> quadtone inksets used together. It gets a neutral tone by mixing the
> cool and warm together. This is true, yes?

No, to simplify, with respect to making neutral prints the variable tone
inksets have 2 "channels" -- one pure carbon warm and one carbon with "blue"
pigments mixed in to make the ink cool.  (The mix that goes into the "blue"
toner varies -- basically cyan and magenta or R800 blue.)

What is important to note is that the warm channel is pure carbon -- no
color pigments at all.  It is not a "magenta" channel.  Actually MIS carbon
is essentially a low gamut yellow.


> That the cool ink is cool means that it has a higher percentage of cyan
> pigment ink than the more neutral K7 does.

Yes, but the color is not just cyan.  It's blue (a mix of cyan and magenta
or blue).

> The warm side is similar - it has a higher percentage of magenta pigment
> than the K7 does. It has to to get the warmer tone.

No, this is where the misunderstanding is.  The warm side is pure carbon.
Thus it has less color pigment than a neutral monotone inkset.  The mix of
the cool and warm channels simply brings the total carbon-to-color pigment
ratio to essentially the same as it would be if the mix was uniform in both
channels.

Having a pure carbon channel has been one of my design criteria, because I
want the ability to print a good pure carbon image.  For old photo
reproductions they look great and are the most lightfast.  So far, carbon is
the champ when it comes to longevity.  So, a pure carbon channel has been
one of my bottom line requirements.

> These two inks, warm and cool, are then mixed on the paper to get the
> tone you want. This is how it works, is it not?

Yes, that is correct.  But the warm channel is pure carbon -- no color pigs.

I hope this helps clarify the comparison for you.

Paul
www.PaulRoark.com