[pure-silver] Rodinal availability
- From: Matthew Gaylen <mgaylen@xxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Fri, 02 Sep 2005 10:51:48 -0500
Richard... you mention Rodinal... you can't even buy Rodinal online anymore
because of terrorist-related shipping restrictions. I love Rodinal 1:50 for
Delta 400 (320)... I rotate it 30rpm for 20 minutes in a Jobo 2500 drum on an
old Unicolor roller. Crystal clear 8x10s from 35mm negs - very high acuity -
grainless.
P.S. I'm dumping the old Microphen...
On Friday, September 02, 2005, at 10:26AM, Richard Knoppow
<dickburk@xxxxxxxxxxxxx> wrote:
>
>----- Original Message -----
>From: <Camclicker@xxxxxxx>
>To: <pure-silver@xxxxxxxxxxxxx>
>Sent: Friday, September 02, 2005 8:19 AM
>Subject: [pure-silver] POTASSIUM -Vs- SODIUM...
>
>
>> ...CARBONATE
>>
>> The formula for Pyrocat HD that I have calls for 75 g
>> Potassium Carbonate in
>> Part B.
>>
>> The "Calls For, You Got" section of the Cookbook suggests
>> Sodium Carbonate
>> can be used in place of Potassium by using 1.12 time the
>> amount of Potassium.
>>
>> I don't question this to be true but there must be a
>> difference in the final
>> product -- no? If you don't use Potassium won't you loose
>> something or gain
>> something you probably don't want? Or are the results
>> interpreted as equal?
>>
>>
>> Bruce
>> Brooklyn, NY
>> camclicker@xxxxxxx
>> www.camclicker.com
>>
> Supposedly, potassium salts are slightly more active in
>photographic solutions than sodium but this is somewhat
>controversial. Generally anhydrous sodium carbonate can be
>interchanged weight for weight with potassium carbonate.
>Potassium salts are common in Agfa formula because they made
>their own as a by-product of something, and got it cheap.
>Potassium carbonate and Potassium hydroxide can be dissolved
>to a higher concentration than sodium salts so are popular
>for highly concentrated solutions (like Rodinal). However
>Potassium carbonate is desiquescent and not as stable as
>sodium carbonate in storage. Kodak used to recommend
>potassium carbonate for motion picture labs beause any that
>got into the air would stick to whatever it landed on
>instead of continuing to blow around.
> Supposedly warm tone paper developers are slightly warmer
>when mixed with Potassium salts. I've seen no actual
>evidence of this.
>---
>Richard Knoppow
>Los Angeles, CA, USA
>dickburk@xxxxxxxxxxxxx
>
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--
joe suburbs the post modern hyper rural sub urban anti hero and vertiginous
surrealist
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