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Promicrol Formula


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Several posts have lamented the missing May & Baker Promicrol

developer over the years. I dug out my 1963 Photo-Lab Index and got

the patent # reference for that developer (2610122). I then did a

patent search and came up with the formula--


N-(beta-hydroxyethyl)-o-aminophenol sulfate 6 grams


Glycin..................................... 1.3 gram


Sodium Sulfite............................. 100 grams


Sodium Carbonate........................... 11.5 grams


Sodium Hexametaphosphate................... 1.7 grams


Water to make.............................. 1 liter


In the first formula there was Potassium Bromide(.6 grams) and no

Glycin.But they added the Glycin for speed and dropped the Pot.

bromide as the fog levels weren't that high (according to the patent



You will notice that this is close to the posted formula for A49.

Except they use Pyrocat. and Hydroquinone instead of the Glycin

( adding the Potassium Bromide for developer fog).


One final note, In the same PLI (1963) there is a note that this agent

(N-(beta-hydroxyethyl)-o-aminophenol sulfate) is NOT a PPD family

member. Maybe one of you out there has more information. I do know

that Agfa (according to further patent searches) was using it in a

lot of it's developers.


Lastly, Silverprint.uk offers a "replacement" Promicrol in there

chemistry line of their website.




That's all for now!

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I remember using Promicrol in the mid to late seventies. If I recall correctly it was a fairly soft working developer that gave moderately low contrast negatives. I also remember that at high dilutions (which I used for economy in those days, knowing nothing about compensation effects), development times were quite long. Any other thoughts or insights out there?



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My chem. friends on the Pure-Silver list say it is of the Aminophenol family. P-Aminophenol being the agent in Rodinal. But this is the RARE and EXPENSIVE O-aminophenol. So you might hsve to check out the A49

formula or the "NEW" Promicrol at Silverprint.uk.

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  • 1 year later...

Hello Garry,


your patent search sounds great. I have bought the 'new Promicrol' but I think it is a different formula, because it mentions 'Hydrochinon sodium sulfite' on the packaging. Or am I mistaken?


Another question: in my fathers foto-magazines from 1967 I saw different pictures that where developed in the Fabofin developer and they look really good. Do you have any possibility to uncover the formula?

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  • 1 month later...

I was so unhappy when Promicrol disappeared, that I tried to have some "HEAP" sulphate (sulfate) made up. In 1992, a Japanese company would manufacture me 2Kgs for US$8,000. I guess that would have made quite a bit of Promicrol and I suppose 20Kgs would probably not have cost *that* much more than 2Kgs but it all sounded too much hassle. I successfully used Promicrol (well diluted) with Tech Pan film, rated at 20asa (sic) and the contrast was absolutely continuous tone. The grain was, for all intents and purposes, non existent. Superb results were obtained from Plus-X and HP5/Tri-X (I used to rate the Tri-X at 1600asa). If anyone has any idea how to synthesize HEAP sulphate, I'd be very interested to give it a try.

I still have two tins of the powder, ready for that "special occasion". In the meanwhile, I use Microdol-X and AB55 developer. Not as good as Promicrol though. - IMHO......

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  • 4 years later...
<p>I just found a box of Promicrol in my darkroom which I am dismantling and disposing of. It brought back so many memories, along with Technidol and other little gems.. I have already listed it for sale and then decided to check to see if there were any threads in here. I guess it's been a while since anyone brought it up. It's like an episode at my corner drugstore this afternoon where a mother in her mid to late thirties was trying to tell her teenage daughter who Walter Cronkite was. :)</p><div>00TySj-156007584.thumb.jpg.040195628b0bb88b19b0bab5bec85e62.jpg</div>
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  • 3 months later...
  • 4 years later...

Old Promicrol used HEAP Sulfate as stated above in the formulae which is also published in " the darkroom cookbook ".

CASnr. 43100-74-9 which seems to be impossible to get this stuff. HEAP has nothing to do with PPD or OPD which is

often used in old ultra fine grain type developers. The old Agfa Atomal was also using HEAP but in combination of

Pyrocatechine and Hydroquinone. Further here the Potassium Bromide was used.

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