Re: Help with what I believe is a hardening issue

Thank you all for your input.

I decided to begin again and size some new BFK. I received some glyoxal
from the Formulary today.

I will admit I may have been a bit lackadaisical at times with the gelatin.
With the last batch I may have let it set out a good while after initially
adding it t the cool water for heating it for the first coat. So far on the
new BFK I have done only the shrinking step and plan to complete the sizing
process tomorrow. I want to try and avoid whatever
mistake(s) I made on the last batch. To that end I have a few more
questions.

In answer to the suggestions below, I am sure the gelatin was the correct
formula-four .25 ounce packet of gelatin to a liter of water. The speckling
is very much in the non-image areas. Also, I always develop the prints in
water at 75-77 degrees which I arbitrarily picked because that is what the
ground water runs here in Memphis during the summer months. The most likely
suggestion is the spoilage issue.

The first question: Is it possible to get the gelatin too hot when sizing?
I heat it in a microwave to the point that I am unable to put my finger in
for more than a second. There is usually steam coming off the surface.
Could this be related to my speckling problem and related to developing
prints in scalding water?

In regard to the glyoxal, I have never used it before, so I have a couple of
questions. The Formulary said to use in the ratio 15ml to 1 liter of water.
Does any one have a different ratio? Do you use it after each coating? Is
10 minutes a good length of time?

In the past, when things have gone wrong I have not concerned myself much
about it because there was no particular dead line- this time I am under the
gun.

BTW the reason I suspected the formaldehyde was information I got from:
http://www.biotech.ufl.edu/EM/data/form.html

It says:
We have been doing some research about the shelf life of 37% Formaldehyde.
There is no definitive age after which 37% Formaldehyde is no longer useful
as a stock solution. Formaldehyde chemistry is moderately complex, but after
discussions with other microscopists, manufacturers and reviewing pertinent
texts, the following observations are applicable. Formaldehyde should be
stored at room temperature, cold temperatures encourage the formation of
trioxymethylene with a resulting white precipitate. Formaldehyde should be
stored tightly sealed, since exposure to air encourages the oxidation of
formaldehyde to formic acid (37% formaldehyde is usually shipped with 10-15%
methanol to inhibit this change). Our recommendation is, if the 37%
formaldehyde solution is clear, colorless and has no precipitate, and has
been stored at room temperature in a tightly sealed bottle that has not been
exposed to sunlight, it should be good, however, we still do not recommend
using a stock bottle that is older than 1 year, bottles that are already
opened should not be used more than 6 months. Consequently, we recommend
that labs purchase their formaldehyde more frequently and in smaller
quantities than perhaps they have done in the past.
*************************************************************
There's more, but this should suffice. The only additional comment is that
37% formaldehyde is not recommended for EM work and that a higher grade
"methanol-free" formaldehyde or a solution made from paraformaldehyde should
be used instead.
Thanks for your help:-{)
Douglas W. Cromey, M.S.
dcromey@ccit.arizona.edu

Thank you all for any and all help,

Candace Spearman

----- Original Message -----
From: "Judy Seigel" <jseigel@panix.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Wednesday, November 10, 2004 12:28 AM
Subject: Re: Help with what I believe is a hardening issue

>
> Formaldehyde is a preservative; it does not go bad. I've kept the same
> bottle for 10 years, or longer, in fact until the contents dried into a
> white powder at the bottom of the bottle. Sarah Van Keuren proudly
> declares she's worked out of the same muddy old tub of working solution
> formaldehyde since genesis (practically).
>
> Plus, when gelatin isn't hardened at all, it doesn't do that speckling you
> describe... it simply stains in the whites. Therefore I suggest that
> something else is going wrong...
>
> Here are other causes I've found over the years for speckling:
>
> Making the gelatin too weak... When I began teaching gum I had the formula
> wrong: It's 28 grams per litre. For some reason I'd been using about half
> that... and after a week of testing, discovered the error.
>
> Another case of speckling was created by a student who was developing his
> prints in scalding water.
>
> Something that looks mighty like speckling can occur if you slap the sheet
> of paper with wet gelatin on it into another, so that the gelatin pulls,
> or forms bubbles.
>
> Speckling can also occur if your gelatin has spoiled, which it can do in
> as little as a day when left out at room temperature. I'd also check the
> pattern of the speckling -- if it's image-specific, it's probably
> something in the emulsion. (Have you changed gums or some other
> ingredient lately?) If it's just free floating, especially in non-image
> areas, then odds are it's the size.
>
> But again,formaldehyde preserves corpses forever -- it doesn't spoil...
> unless of course it was contaminated to begin with ?!
>
> PS. the last formaldehyde I bought I got from the drug store by
> prescription. Do you have a family doctor? A nice one might well oblige.
> Also, TALAS had it in their catalog years ago. Might still.
>
> Judy
>
Received on Wed Nov 10 18:36:41 2004