From: Eric Neilsen (e.neilsen@worldnet.att.net)
Date: 03/31/02-09:44:51 PM Z
Clyde, It sounds like your problem is mixing the coating solution with too
much "B" or #2. I would also expect your results to show a bit of grain.
You also failed to mention any drying or humidifying of the paper. If you
are using a 50/50 mix of metal this may not be that bad but if you are using
only platinum and printing humid, that may also be a problem with printing
speed.
Try this. 8 drops Ferric #1, 4 drops each PT and PD. Dry with hair dry
for 6 minutes and print. Expose Step tablet for 10 minutes. You should see
black up to Step 3 to 4 with separation up to 16 maybe a little less.
Prewarm tubes for 10 minutes before your exposure. Regular glass may also be
preventing some exposure in the low UV range.
Good luck
EJ Neilsen
----- Original Message -----
From: "xrogers" <xrogers@attbi.com>
To: <alt-photo-process-l@usask.ca>
Sent: Sunday, March 31, 2002 11:52 AM
Subject: beginner seeks help---long pt/pd exposure times
> Hello, all. This is my first message to the list---a couple years of
> lurking bites the dust.
>
> I'm trying out platinum/palladium printing. My exposure times to get two
> steps of maximum black on a Stouffer step wedge are more than 30 minutes,
> and I'm doing about 20 minute exposures for negatives.
>
> I'm using a home-built light box with 8 Sylvania F20T12BL tubes (about
1/4"
> between tubes) and two UltraLux electronic ballasts. My printing frame
puts
> the paper about two inches from the tubes. I took the basic design from
the
> Edward's Engineering web site (which claims the box should expose pt/pd in
> about 5 minutes), and got pointers to the ballasts from Sandy King's
> excellent UV light source article.
>
> My palladium salts are about six years old, and platinum and oxalate are a
> month old, from B&S. I'm coating crane's platinotype white with a glass
> rod, and using about 16 drops total for the 4x5 step wedge. Developer is
> ammonium citrate, about six years old, at about 85 degrees. Oxalate and
> salts are room temperature, between 60 and 65 in the Minnesota basement.
I
> do get a decent black with enough exposure, so I've assumed I don't need
to
> warm up the salts.
>
> So, are these times to be expected? Have I messed up the light source
> somehow? Is there an easy way to test the light's intensity? Am I doing
> some other obvious, stupid thing along the way?
>
> Thanks for any help,
>
> --clyde rogers
>
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