Eric Neilsen (e.neilsen@worldnet.att.net)
Thu, 25 Nov 1999 10:36:31 -0600
Judy Seigel wrote:
>
> On Tue, 23 Nov 1999, David J. Romano wrote:
>
> > Joe,
> > I've been researching light sources for a while because I'm building an
> > enlarger for platinum printing. None of the sources are as inexpensive
> > as the one Ed Stander suggested though. Keep in mind that any glass,
> > like your contact frame must be able to transmit the wavelengths you
> > need. That issue alone could be the topic of a long thread. Here are
> > links to some vendors I've found.
>
> and bear in mind that the "water white" (was it Starfire?) glass may or
> may not be an improvement. I spent $125 or so for a vacuum easel "clear",
> then ditched it for plain old $25 "green" glass because it didn't print
> gum as well. For gum the "clear" was, as I recall, about 10% faster, for
> platinum I gather the speed gain is somewhat more -- if it matters.
>
> Judy
Dave , What information can you share about UV transmission of different
lens that you are using? What kind of light has the ability to output enough
UV without the heat that would melt a negative or at the very least make it
move during exposure?
The Starphire glass does have different light transmission than that of
standard clear or green glass. It is however, very important to know the
light transmission of your light source and the sensitivity of your material
before any conclusions can be drawn about printing speeds +/-.
-- Eric J. Neilsen 4101 Commerce Street, Suite #9 Dallas, TX 75226 214-827-8301 http://home.att.net/~e.neilsen
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