Digital BW, The Print

Just a data point for what its worth...

I made a pseudo-custom inkset for the 7600 controlled by QTR. I left the PK,LM,LC UC 
inks in place, and replaced the C M Y and LK with the  UT FS inks.  I then used the LM and 
LC as toners. I bought empty carts and filled from bulk (since I used non UT2/7 ink 
positions).

I needed to add a bit of code to Roy's script (based on how he did the curves for UC)  to do 
the toner this way, but it worked very nicely. I added the LM and LC based on the density 
of the C M and Y channels. The overall amounts of LC and LM are set by the ink limits for 
those channels.  I measured a selenium toned sliver print (eyeone) and fiddled with the 
limits to get a good color match. I then did a final linearization to take the toning density 
into account.

You can see the LM and LC dots if you look with a loupe - a slightly lighter toner would 
perhaps do better in this regard.  Without a loupe the toning looks just great and balanced 
throughout the scale.

Costa Colbert

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul Roark" <paul.roark@v...> 
wrote:
> James,
> 
> >I have been experimenting with the MIS UT7 inkset on a SP2200.
> 
> >... the UT7 inkset only provides 3 Black inks 
> >while having 3 toners and a "custom light black"
> 
> The black/gray inks in the UT7 are the black, light black, cyan, and light
> cyan.
> 
> In addition, the cool toners in both the UT7 and UT2 inksets have a lot of
> carbon in them.  They are about the same densities as the dark and light
> pure carbon inks.  It's a different approach to "toning" than in the
> original VM and UT1 inksets.  The cool inks contribute significantly to the
> overall density of the image.  This makes for better glossy printing, where
> the light inks flood the paper and cause spots.
> 
> >Are there any visible dis-advantages to having only 3 black densities? 
> >It seems like this could be less desirable in theory than the 4 black 
> >densities of the UT2 inkset.
> 
> The UT7 inkset is close to the UT2 in basic approach and design, with the
> addition, of course, of a light black.  So, there are actually more gray
> inks in the UT7.  Also, with the separate carts, one can put an extra light
> gray in the yellow spot of the UT7.
> 
> Compared to the UT1 and FS inksets, what the UT2 and UT7 lack is a very
> light gray (like the old FS Y ink, a density that was designed to allow the
> old 3000 to print smoothly).  This is why the UT2 and UT7 inksets should not
> be used on older printers.
> 
> >Why would one use the "custom light black"?
> 
> The light gray ink is mostly used by the driver when R=G=B.  It is there
> mostly to fight metamerism in the color inksets when the shadow tones are
> neutral and would show it the worst.  In the UT7 inkset, the LK ink is used
> mostly where grayscale files are printed with the sliders, and the sliders
> are left in the neutral positions.  The target tone here is slightly warm.
> However, when the standard LK kicked in, it caused a warm cross-over in the
> shadows.  Then, when the Eboni kicked in lower in the shadows the hue
> shifted back to only slightly warm, Eboni being much more neutral than the
> OEM Epson Matte Black.  So, the UT7 LK tone was matched to the 50%, slightly
> warm hue of the "EZ" (grayscale, no curves, sliders at 0) default printing
> mode tone.  
> 
> >Why would one choose the UT7 inkset over the UT2 inkset for QTR?
> 
> The only ink that is common between the two is the dark gray, and it is in a
> different position.  The differences are needed to allow each printer to hit
> the target densities and tones (hues) in the "EZ" mode -- and they are very
> different printers.  The two drivers' assumptions about the ink
> characteristics vary because of the differences between the Epson dyes and
> pigments.  The UT2 and UT7 inksets, however, basically use the same
> approach.
> 
> I don't know how all this would relate to finding the optimum mix for QTR.
> 
> Paul
> www.PaulRoark.com