RE: Humidity and Sensitivity... Platinum  and so on...

And it is true for FO as well as AFO printing.

Eric Neilsen Photography

4101 Commerce Street

Suite 9

Dallas, TX 75226

http://e.neilsen.home.att.net

http://ericneilsenphotography.com

-----Original Message-----
From: Ender100@aol.com [mailto:Ender100@aol.com]
Sent: Thursday, August 05, 2004 12:29 PM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Humidity and Sensitivity... Platinum and so on...

Eric,

Very well said.

I became fully aware of the effect of temperature and humidity with PT/PD
when I was putting together the Precision Digital Negative system. It was
really driven home late last fall when the furnace kicked in and printing
suddenly went to pieces. I bought a nice little digital
thermometer/hygrometer from Ace Hardware for about $20. That coupled with a
nice little Holms Humidifier has resulted in no problem since then. I found
that maintaining a level of relative humidity in the 50-60% range was
important to good printing with PT/PD and had this confirmed by a number of
expert printers.

I finally standardized on a specific humidity level and a method of
pre-humidifying my paper before coating and a specific drying time and
method. The system I am using for printing with digital negatives will
indicate very slight variances.

It is much easier to control a situation where you have low humidity than
high humidity, since it is easier to add than subtract. Places where there
is very very high humidity on a regular basis must present a real problem.

I think people around the country have very different humidity issues or
non-issues, depending on the consistency of the relative humidity and
variance with seasons. Most people have probable just built it into their
workflow—sometimes without being aware that they were doing so, but getting
good results just the same. I think it is probably one of the most important
and most ignored issues in printing.

Mark Nelson
www.precisiondigitalnegatives.com

In a message dated 8/5/04 9:45:30 AM, e.neilsen@worldnet.att.net writes:

Ray, Heat and Humidity are ALWAYS important throughout the process. That
being said, it is not always critical nor does it remain the same issue at
each phase of the print production process. The paper will get treated by
the practitioner before the coating of the sensitizer, gum, sizing, et la.
The coated paper is then handled carefully to the next step, and so on until
the finished print lay on the table with the eyes of its creator lovingly
looking down upon it. With the platinum/palladium family of print making,
humidity affects the way the coating solution is absorbed and thus how much
or how little solution to use. In the drying of the paper, it
allows/prevents the penetration of the solution. In the exposure it plays a
roll in speed, color and contrast.

AS you print, you begin to see how critical control of humidity and heat
become. This understanding and others like it can allow you to control the
process rather than it controlling you.

Have fun!

Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://e.neilsen.home.att.net
http://ericneilsenphotography.com
Received on Thu Aug 5 20:37:34 2004