RE: Mike Ware's POP Pt./Pd. Pt

[Loris Medici <mail@loris.medici.name>]

Hi Sandy,

What is your coating / drying procedure?

-----Original Message-----
From: Sandy King [mailto:sanking@clemson.edu] 
Sent: 10 Kasım 2006 Cuma 08:23
To: alt-photo-process-l@usask.ca
Subject: RE: Mike Ware's POP Pt./Pd. Pt


One issue I have seen with a few of the AFO 
PT./Pd. is small white spots, irregular in shape 
and some larger than others, and all in the 
shadows and lower mid-tones. I suspect that they 
may be caused by the sensitizer separating from 
the paper during exposure, or more likely when 
the negative is separated from the paper after 
exposure, perhaps due to moisture content. I use 
a vacuum frame and the pressure, even though not 
great, may cause the separation. With FO Pt./PD I 
typically dry the coated paper only about fifteen 
minutes and have never had this kind of issue. 
With the POP process I am finding that there is 
some risk of the white spots unless drying times 
are much longer. As I mentioned earlier, I am 
working in a room with RH of about 50-55%.

Of course, the problem might be something else, 
such as something in the sensitizer or method of 
coating. I am very new to this method of printing 
and still trying to learn to recognizes the cause 
of problems.