QTR-Quadtone RIP

I took up Roy's suggestion that "it might be interesting to use a
gradient of text from black to very light gray to see where the text
clarity visibility peters out."  I did this a few days ago, but
unfortunately haven't had time to post the results until now.

I put a gradient over the 1 point test file to produce all those
shades of gray. I loaded the file to the "Tools" section of the QTR
group webpages.  You can find it here:
http://f1.grp.yahoofs.com/v1/MLTDSAfDErB-gCkHjxMi9KKEOpzpcM4SpgAUohEKbLvO59AXVZskddTJ9UG0j0h3gXN8aRc7F_ht3d4AQmSsCXlFmmCNuWs/Tools/piezoTypetest-gradient.jpg

Printing the file yielded a new set of results.  The QTR-K7 print on
matte paper was clearly superior to the 4800-K3-color ink print on the
same paper.  100% crops of scans of the prints only tell part of the
story, so I've posted the scan of the entire half inch print area in
the "Photos" section.  You can find them here:
http://tech.ph.groups.yahoo.com/group/QuadtoneRIP/photos/browse/5453?c= 
The K3-color ink prints appears to have produced a color cast around
transition of middle gray tones, and some fine banding is evident.  I
wanted to see what Epson's Advanced Black and White (ABW) could do
with this, but since the driver with the 4800 apparently does not
allow ABW to be used on matte paper (does anyone know why this is?), I
printed the test file on semi-gloss paper. Quite frankly, this was the
best print -- better than the QTR-K7 inks -- but I attribute that, at
least in part, to the semi-gloss paper.


--- In QuadtoneRIP@yahoogroups.com, "Roy Harrington" <roy@...> wrote:
>
> That's an interesting set of tests.   The scatter look from the K3 ABW
> test is a curious
> phenomena.  Since this is the Epson driver I can only guess what's
going on.
> I highly doubt it has anything to do with resampling.  The extra dots
> are just too far apart
> to be mechanical spraying, or resample related IMO.  Some diffusion
> dither algorithms can
> produce that kind of artifact so that would be my guess.  The fact
> that the text is diagonal
> may help with seeing it.  My prints, all done with QTR, do not show
> anything like that --
> Ordered Dither which I recommend and use will not produce that kind
of artifact.
> 
> At least with QTR I'd expect the different inksets, K3, K7, UT7, UT3D
> to all perform similarly
> in the particular test.  After all we're talking black text here.  To
> through out an other idea:
> it might be interesting to use a gradient of text from black to very
> light gray to see where
> the text clarity visibility peters out.
> 
> The 1080ppi issue may be because it theoretically gives a thinner
> line.  Many of the 720
> files show a lot of ink which tends to bleed over.  At 1080 I suspect
> the resampling will
> end up with a lighter gray so you get less ink on the paper.
> 
> Roy