Re: What chemicals I should buy to experiment with home-made developers?

On 22 Jun 2003 20:23:06 -0700, (E-Mail Removed) (Dan Quinn) wrote:

>RE: "Randy Stewart" <(E-Mail Removed)> wrote
>
>> Would the author care to step forward and give us a few common examples in
>> support of this sweeping comment that newly mixed chemistry is not
>> [chemically] stable for use?
>>
>> And, why would newly mixed chemistry be stable for a few films or prints but
>> not for "many"?
>
> I'm not the author. Stable enough for use might be more correct. Some
>developers are to be used without any delay. Any borate, ortho, meta or
>tetra, based developer is better left a day or more before use. Borax,
>sodium tetraborate undergoes hydration and hydrolysis. Hydration con-
>ferts it to meta then ortho. The confersion takes time. Hydrolysis
>also takes time. All in all the solution becomes more alkaline.
> As I've mentioned in an earlier post this thread, I've noticed ph
>drift over time. I've not tested borax but have noticed it with
>carbonate and thiosulfate. Of course a little drift upward with
>fix is of no concern but with developers it is. Dan

I heard the "wait" advice in the way distant past and ignored it until
one evening in the mid-70s when I made up FX-4, or a variant. I was
impatient to get a set of tests done and get to sleep, so I forced the
temperature down with an external ice bat after mixing at around 125
degrees. The result was a 2 stop increase in speed.

I was so shocked that I set the unused half of the fresh mixed
developer aside ln a sealed, smaller bottle. The next morning, I
developed a second test strip from the sme roll. It had no speed
increase and was spot on for all characteristics. This happened using
water from the Manhattan water supply.

After thyat, I began to look for differences between freshly made
solutions and settled ones. Invariably, the ones that showed any
difference, and not all the time, were BW developers, usually
containing around 100 g Sulfite and Forates as the alkalis. This
ocurred when the formulae were mixed fresh from powders or crystals,
never when mixed from stock solutions, or when the freshly mixed
formula was diluted more than half with water for use.

As a result of these observations, I adopted the "waitm and use " rule
for everything; just in case. Consistency of results was never a
problem for me since then, at least with my own mixed formulations. I
used water from city supply in Los Angeles, San Francisco, Manhattan,
Hoboken, the Catskills and the Poconos with invarying results.

This rule is a keeper for me.,


Robert Vervoordt