Smieglitz@aol.com
Date: 07/04/01-08:26:47 PM Z
In a message dated 07/04/2001 21:12:57, holtsg@duke.usask.ca wrote:
<<I'm dying to do digital gum. Any opinions on using a humble Epson stylus
photo 700 to print the negatives. I'd reconcile poor resolution just to
get know how it works with what I have.
I have some ideas about false coloring black and white pinhole images and
printing them with gum.
>>>
Hi Gordon,
I think any problem you might encounter with the Epson 700 or similar
printers will have to do with the ink pooling on the transparency material.
I've tried several different brands with an Epson 600 and had best results
with Epson's own transparency material. But, I suspect the Pictorico OHP
will work even better. The Epson material has sort of a regular dotted
texture that seems to act as ink wells. The Pictorico has a coating
(gelatin?) that provides a better substrate, at least with the Epson 1160.
(I haven't used the 600 for negatives since acquiring the 1160 model and Cone
inkset.)
The ink density will be greater if you use black ink only, but then you will
run into the drying and pooling problem along with higher contrast. (I used
to make the negs using a diffusion-dither bitmap file at around 200dpi with
black ink similar to Phil Davis' method with laser transparencies, but the
following gives better results.) You will be able to get a smoother output
using the color ink setting to print a monochrome negative transparency. For
best results, fool the printer driver by selecting a media type such as
"Epson Photo Quality Glossy Paper" or "E.P.Q.G. Film" as this will allow you
to use the "microweave" option @ 1440 dpi. If you wish, Photoshop can be
used to color separate a CMYK image file and print the 4 negatives
automatically. But, this changes the original RGB file info a bit, so I
usually just print the 3 channels from the RGB file.
By all means give the 700 a try. Although the dots will be slightly
apparent, the gum printing process tends to eliminate them in the print.
Slight misregistration and dimensional instability of the paper with multiple
printings and wet/dry cycles tends to fill in the spaces between the dots.
The result is very acceptable with the multiple gum process (although I find
the dot pattern distracting in single coat cyanotypes or VDBs.)
You might find lower contrast files will print better. (There seems to be a
huge jump in %ink output on one end of the scale with the Epson printers.)
The contrast can be adjusted in Photoshop's curves or levels dialog box
without clipping the file data. (OTOH, the brightness/contrast control
eliminates data, so I wouldn't use it.) I also suspect the adjustment curve
I posted a few days ago will produce better output of the channels on the 700
or similar printers, although I haven't tested it on models other than the
1160 with the quadtone inks. With that system the curve essentially
eliminates the jump in %ink towards the upper end of the scale and produces a
low contrast negative that prints about 6 steps of a Stauffer wedge at max D
with minimum time with a single gum coat.
Let me know if you have any questions as you give it a try. I'd also like to
see the results.
Joe
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