U of S | Mailing List Archive | alt-photo-process-l | RE: Potentially stupid pt/pd question

RE: Potentially stupid pt/pd question

For clearing try using a 3 % solution of citric acid for 5 minutes directly
after the developer without a water bath. Clear in Kodak hypo clearing agent
@ a 1:3 dilution from stock for 5 minutes in the next two baths. Wash.

-----Original Message-----
From: Camden Hardy [mailto:camden@hardyphotography.net] 
Sent: Friday, October 13, 2006 7:10 PM
To: alt-photo-process-l@usask.ca
Subject: Potentially stupid pt/pd question

I started calibrating my new shipment of Coventry Rag Vellum paper, which
Legion assured me was te same as their Coventry Rag (thanks to Eric for
the recommendation and sample).  Right out of the box, I could tell you
that it's not the same.  But I swiped it with a pH pen, and at least
looked acidic enough for pt/pd, so I decided to give it a try.

I'll start with my workflow.  I pre-humidified the paper at 55% RH for a
half hour, coated, then let it dry in 55% RH for another half hour.  I
exposed a 31-step tablet for 6 minutes, developed in potassium oxalate
(100 degrees F), cleared in hypoclear+EDTA.  This has been my normal
workflow and until now proven to work well.

Now here's what I'm encountering.  First of all, the Dmax is nowhere near
what I would have expected.  I don't have access to a working
densitometer, but I'm guessing it's about 0.9.  The other issue is that it
took twice as long to clear as any other paper I've used.

So here's my question.  What are the possible causes for this?  Are these
issues independent of each other, or could they have the same cause?


Camden Hardy