RE: Vandyke Question
May I stick in my two cents on the subject of distilled water in regard to
the problem? I have bought commercial distilled water at the hardware store
for use with our iron at the family ironing board, and used some in my
chemistry, as well as my home distillate. Never a problem with
either,although I am certain that neither is genuinely "pure". I would
expect that, for the water to be the problem it would have to be so grossly
contaminated that you would smell it down the corridor. My money is on the
silver salt being contaminated, and I will raise the bid to three cents.
From: Judy Seigel [mailto:email@example.com]
Sent: Sunday, February 24, 2008 3:43 PM
Subject: Re: Vandyke Question
My only "expertise" in VDB is from mixing it in my own studio & observing
all those space cadet undergrads have at it... The only failures we
experienced were easily diagnosed: in one case a metal cover on one jar of
solution (whichever it was) was an obvious contaminant, in the other (as
noted) the supposedly distilled water (sealed in an "official" distilled
label) turned out to be regular tap water. But beyond that we stirred fast
or slow, & probably committed a dozen other breaches without trouble, tho
come to think of it I got a call from the department last semester about
some VDB trouble (which I think was ultimately traced to contaminated
silver jar, but I'll see if I can check back on that).
But, given the far better care you have obviously exercised, my guess
would be that there's another factor at work, that for instance one of
your chemicals could be below par. Have you made the emulsion from these
chemicals successfully, or with less hassle, in the past?
Which, if any, is new? My own experience with other emulsions is that
ferric ammonium citrate can arrive bad or turn bad (I recently had to
throw out half a pound that turned into cement, tho granted it was
ancient). Is the silver nitrate white white & quite crystal? Tartaric
acid I can't comment on since we worked off the same jar forever. And I
assume of course that given your general meticulosity your beakers and
stirrers are clean...
My only other comment at this point is that I, too, have used VDB emulsion
more than a year old without a problem. The inside of the jar seems to
plate with silver fairly soon, without any noticeable effect on the print,
and old emulsion will have black specks which reabsorb as soon as the
solution is smoothed on the paper.
On Sat, 23 Feb 2008, Scott Wainer wrote:
> 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
> 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
> 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
> everything was fine until I got to the last 7-8 ml then it started to
> up. How vigorous should the stirring be? I stir enough to create a small
> whirlpool and switch direction often.
> Best to all, Scott