From: Dave Rose (photo@wir.net)
Date: 02/05/01-06:57:10 PM Z
Hello Judy,
----- Original Message -----
From: "Judy Seigel" <jseigel@panix.com>
> On Mon, 5 Feb 2001, Dave Rose wrote:
>
> > > The light goes through the polyester?
> >
> > + Yes, the polyester is "Kleerbase" brand. It's used in the printing
trade,
> > and as the name suggests, is clear and transmits light.
>
>
> And optically pure? Have you tried, for instance, a resolution test
> through it? Or a distortion test? (If it is, I want some. Any special
> thickness?)
+ I'm not sure if it's "optically pure". I haven't done any critical tests
with the material, but then, I don't think the application demands such
fussiness. The polyester is between the UV light source and the negative,
so any minor smudges, scratches, or very small particles of dust make no
discernable difference in print quality..... at least with gum prints. When
the polyester gets really 'ratty looking', I'll replace it with a fresh
piece. I have most of a 100-sheet box left, so I've probably still got half
a lifetime's supply. The thickness is 0.005 inches.
> > + B&W original
> > 1. Contact print the negative onto another sheet of 4x5, to create an
> > interpositive.
> > 2. Enlarge onto lith film, to the size desired.
> > Color transparency original
> > 1. Create a highlight mask, register it with the chrome, and then make
a
> > contrast mask.
> > 2. Enlarge the masked chrome onto lith film, to the size desired.
> > Note: with a very low-contrast chrome, it's sometimes possible to skip
step
> > 1.
>
> And the color separations?
To date, all of my color separations are in-camera originals, on 4x5 B&W
film. Enlarged negatives were made as above. After the enlarged color seps
are made, I register them by eye, tape them together, and punch holes for
the registration pins. When I'm not busing doing twenty other projects,
I'll try enlarging masked 4x5 chromes onto some Kodak 4133 film that I have.
Best regards,
Dave in Wyoming
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