U of S | Mailing List Archive | alt-photo-process-l | Re: Vandyke Question

Re: Vandyke Question

----- Original Message ----- From: "Scott Wainer" <swphoto@verizon.net>
To: <alt-photo-process-l@usask.ca>
Sent: Saturday, February 23, 2008 5:33 PM
Subject: Re: Vandyke Question

The first two batches of sensitizer were made with water from my steam distiller. The last 6+ batches were made from distilled bought at the local food store. I checked the label and it doesn't say how it was made.

As a side note, I drink a lot of flavored water and just looked at the label. It says "purified water" so i'm now wondering ....

I am a stickler for things like this. I used a calibrated thermometer and kept all solutions between 110-120 F. Constant stirring and everything is added slowly. On the last batch part c was added at about a drop a second and everything was fine until I got to the last 7-8 ml then it started to cloud up. How vigorous should the stirring be? I stir enough to create a small whirlpool and switch direction often.

Best to all, Scott
Its important to know just what impurities are important to a particular process. For instance plain tap water, providing its clean, is quite suitable for most conventional photographic processes. Hard water can often be at least partially softened just by boiling it for several minutes. This will drive out some types of dissolved gases (but not all) and will deposit some hardness as a crust on the vessel. By using an activated charcoal filter (like a Brita filter) in addition to boiling its possible to get reasonably pure water at low cost.
There was a story a few months ago about a popular brand of bottled fancy water that turned out to be just plain tap water. I think the company had to change their labels.
Note that genuinely chemically pure water tastes pretty flat, or in the words of Pogo Possum, 'This water has too much of a tasteless taste."

Richard Knoppow
Los Angeles, CA, USA