QTR-Quadtone RIP

This is an interesting experiment.  I regularly use a 3800 with K3 inks and QTR.
So I tried a few prints.  These are Harman paper with photo black.

Here are three scans -- scanned at 3200, sharped like Paul's and
reduced to 1600dpi.

1)  My regular setup:  1440super, bi-directional,  mixture of curves.
2)  2880dpi, uni-directional, same curves, these have a little too much ink so:
3)  2880dpi, uni-directional, same curves, but the image density was reduced.

See:  http://www.harrington.com/restest1.jpg

It looks to me that the biggest issue is using 2880dpi for printing.

Roy

On Sat, Aug 30, 2008 at 3:31 PM, Paul Roark <paul.roark@...> wrote:
>
>>If this now famous 1 pt image file would be made available
>>we could make our own opinion.
>
> I've used resolution test files for some time that I simply make in
> Photoshop.  I believe the top resolution of the Epson driver is 720 ppi, so
> that is what the file is.  It can be downloaded at
> http://www.paulroark.com/BW-Info/Resolution-chart-720ppi.jpg
> (There does not appear to be any difference between this Jpeg and the Tiff
> original.)  The file is 1" x 0.3".
>
> I've added a "one point" text sample to this.  There are 72 points per inch
> in the current U.S. method, according to Wikipedia
> (http://en.wikipedia.org/wiki/Point_(typography))  So one point text is 10
> pixels high in a 720 ppi file.  This includes the top of the tallest capital
> letter and the lowest tail, in addition to a 1 pixel top margin.  This is
> really small.  I used the PS text function to make 10 point text in a file
> that was 7200 ppi and then resized to 720 ppi.  I made one of the text
> sections with no anti-aliasing, and one with "crisp" anti-aliasing.  Given
> the few pixels involved, neither is particularly good even on the monitor.
>
> Evaluating the printed images is tough if one does not have a very good
> scanner.  Seeing the details is a bit beyond the limits of my 1600 dpi Epson
> flatbed, but after sharpening 125% PS, one can start to evaluate the
> relative quality of the printing.
> See http://www.paulroark.com/BW-Info/Resolution-comparison.jpg
>
> I've included a screen grab of the Piezo test in the above image.
>
> A drum scanner is really needed for this task.  On the other hand, with a
> good loupe, one can see more than my scanner, and the text is actually
> readable -- with some effort.
>
> The bottom line I saw was that with the 2200 and 1400, with Carbon-7 and
> Eboni-6, respectively, and using the Epson driver and QTR, the one point
> type is reasonably clear with all of the above combinations.  There is no
> significant difference between the Epson driver and QTR.  The 1400 is a bit
> sharper than the 2200, but in normal viewing, one would not see any
> difference.  The Piezo printing from the test on the web appears to be in
> the same league with what I see with the Epson driver or QTR and the inksets
> I use.
>
> I do not have a K3 ABW setup to test.  It would be interesting to see a good
> scan of a print of the above test chart with K3 ABW.
>
> Paul
> www.PaulRoark.com
>
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