Re: Vandyke Question

[Richard Knoppow <dickburk@ix.netcom.com>]

----- 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


> Judy,
> 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 ....
>
> Sam,
> 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
dickburk@ix.netcom.com