Digital BW, The Print

I received samples 1280 output which used the MIS VM variable-tone inkset
printed at 2880 resolution.  As one would expect, it is smooth -- smoother
than anything I've measured so far, including my Piezo 1160 output.

The way I try to get an objective measure of visual smoothness is to use the
Standard Deviation in the Photoshop Histogram tool/function.  I scan at 240
dpi, which is about equal to the generally accepted 5 line pairs/mm
resolution limit of human vision.  All test strips were printer on Archival
Matte paper.

I measure the plain patches of the 21-step test file, so that all of what I
measure is supposed to be the same density.  Ideally, there would be no
deviations from the mean at all.  However, dots and microbanding are
realities of the inkjet process, and I assume what I am mostly measuring is
a combination of those two factors.

Here are the results at different density patches:

5%  1160 Piezo SD = 1.08; 1160 VM = 1.96;  1280 VM @ 2880 = 1.06;

20% 1160 Piezo SD = 1.32; 1160 VM = 1.94;  1280 VM @ 2880 = 1.51;

50% 1160 Piezo SD = 2.22; 1160 VM = 1.94;  1280 VM @ 2880 = 1.60;

75% 1160 Piezo SD = 3.90; 1160 VM = 3.03;  1280 VM @ 2880 = 2.91;

95% 1160 Piezo SD = 4.16; 1160 VM = 3.64;  1280 VM @ 2880 = 2.82.


These are just measures from one 1160 and 1280, so your mileage may differ.

Of course, the 1280 at 2880 is slow, and it is almost as good at 1440.  At
1440, it is slightly less smooth than the Piezo at 5% and 20%, but closer to
the 1280 @ 2880 at the other noted densities.  The MIS VM test strips
measured above were printed with the "nc" (neutral-cool) curves.  The 1280
with the medium warm curve, is even slightly smoother, presumably because
there is less color contrast from the toner.

Paul
http://www.PaulRoark.com