Richard Knoppow (dickburk@ix.netcom.com)
Sat, 05 Jun 1999 13:02:39 -0700
At 01:37 PM 6/5/99 -0600, you wrote:
>I have a few questions here,
>
>Steve Shapiro wrote:
>
>> Amidol is a staining developing agent that is more acidic and developes
from
>> the base of the emulsion rather than the top of the emulsion down as most
>> do.
>>
>
>Can you substantiate this? This sounds like one of those false statements
that
>have become gospel without proof because they have been repeated so many
times
>by so many people because they "read it somewhere". I am referring
specifically
>to the "develops from the base up" statement. And when you say more acidic,
>more acidic than what? Do you mean it functions atypically in an acidic
>environment?
>
>>
I suspect this is a mixture of things taken out of context. Amidol does
not produce a stain image, but it is a prodigeous stainer of anything it
gets on and oxidizes, hense E.Weston's black fingernails.
Amidol will develop in an acid solution unlike most other reducing
agents. There are some acid Amidol formulas available. The main reason for
doing this is to try to extend the life of the mixed developer. Amidol is
very unstable and tends to oxidize very rapidly. The solutions do not
discolor when exhausted so they may look perfectly good and not work.
I have read a reference to Amidol's supposed ability to depth develop
somewhere but can't at the moment find the reference. I believe it does
this only in special formulas, perhaps when acting in an acid solution. In
any case, this is _not_ a desirable condition for normal negative
development since it would tend to exagerate any problems from irradiation
in the emulsion.
Several reducing agents are acid, Metol amongst them. I don't think this
is what the original poster was refering to.
I was introduced to Amidol for paper developing many years ago. It is
supposed to produce a good neutral black on neutral or cold tone papers and
avoid the greenish olive tone sometimes seen with Dektol. I think you can
gain the same effect by using a Phenidone-Hydroquinone developer of even a
conventional MH developer like Dektol by adding some Benzotriazole to it.
I can't think of any reference to Amidol as an additive to Pyro
developers although it might have some sort of superadditive or protective
function like Metol.
The curious thing is that most of the research in the days when Pyro was
the most popular reducing agent was aimed at eliminating the stain image
because it made the printing quality unpredictable.
>> In theory, and to many photographer's eye in practice, this renders a more
>> complete development with great depth to the image. While some use this
>> combination with PMK in their Jobo, it was mostly used successfully in tray
>> development with big negatives.
>>
>> Amidol has a tendency to oxidise at it's own rate
>
>What does this mean? I don't understand this.
>
>> and with this temperment
>> is not a good developing agent to use with reel or hangar developing
>> methods. I attest to that latter method folly having stained some 4X5 negs
>> using hangars to develop in amidol.
>>
>> I wish to caution you, when using pyrogalol (pyro) even in solution, it
>> gives off an invisible gas that can get under your eyelids and severly
>> damage your eyes and impare eyesight;
>
>You need to elaborate on this some more. What is this "invisible gas" that
>"gets under the eyelids" ???????????
>
>> amidol when breathed into the lungs in
>> the powder form can cause lung damage. It takes such little effort to be
>> careful If your tendency is to mix chemicals carefully with your tongue
>> between your lips, mouth open or if you're prone to agitate trays with your
>> face close to the surface as in on a high counter top Don't bother with
>> these chemicals. There's enough modern developers available. Edward
Weston
>> abandoned pryo and amidol for Edwal FG 7 and Selectol/Dektol during the
last
>> ten years of his photographing.
>>
>> S. Shapiro, Carmel, CA
>> ----- Original Message -----
>> From: Guy Glorieux <glorieux@pop.total.net>
>> To: List Alt-Photo <alt-photo-process-l@skyway.usask.ca>
>> Sent: Friday, June 04, 1999 9:41 AM
>> Subject: What does amidol do?
>
>I appreciate your clearing these up for me. Thanks.
>
>John
>http://www.johnrudiak.com
>
>
>
----
Richard Knoppow
Los Angeles,Ca.
dickburk@ix.netcom.com
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