Adding Amidol to PMK Pyro : LUSENET : B&W Photo - Film & Processing : One Thread

I recently started using PMK Pyro, pre-mixed, and so far so good. I just purchased some amidol to try to move up the EI. Most writers suggest between .05 and .1 grams of amidol per liter of pyro. My problem is that I do not own a scale for weighing out the amidol. But I do have the usual set of kitchen measuring spoons, sarting from 1/4 teaspoon. Can anyone tell me what either .05 or .1 grams would be in terms of measuring spoons. And is that level, or heaped.


-- Alan Shapiro (, September 20, 2001


I have used amidol for paper developer and typically used 6 grams. Amidol is very light weight and I remembered 6 grams is like two kitchen spoons, so 0.1 gram is like 1/30 spoons. I do not know if this helps but I certainly would suggest just a pinch (I would not suggest to use bare fingers though) should be sufficient.

-- Peter Wong (, September 21, 2001.

It doesn't take much. I routinely add .05 grams amidol to the 500ml of PMK solution I use for a roll of 120 film. I'd say 1/10 gram is a little pile that wouldn't quite cover a dime. I'm guessing that a level 1/4 teaspoon is about 4 times too much (i.e., about 4/10ths gram), but that's just a guess. At some point you may wish to be more precise in your measurement, and I recommend a powder scale that reloaders use for weighing gunpowder--they are extremely accurate and cost less than $50. You might even find one on e-Bay. In the case of amidol, less is probably more, as increasing quantities beyond 1/10 gram per liter of working solution merely increases base fog without any additional speed increase.

-- Ed Buffaloe (, September 21, 2001.

According to The Darkroom Cookbook, one teaspoon of amidol = 1.6 grams, so Ed is right; teaspoon would be about .4 of a gram or four times too much.

-- Brian Hinther (, September 22, 2001.

Try this first with film that is NOT IMPORTANT. I do NOT recommend the use of Amidol with PMK. 1. The speed increase is hardly significant, about 1/3 stop in real speed increase 2. It changes significantly the color of the stain. The very useful green stain becomes a brownish to purple-ish stain that lacks the advantages of the green stain with VC paper. Also, I've heard that the pre-mixed PMK is sometimes not correctly mixed. Photographers' Formulary DRY PMK kits are excellent. Better is to mix from stock chemistry. Dial-O- Gram scales are quite cheap at pawn shops. If you don't already have it, get 'The Book of Pyro' and make sure to follow the safety precautions (which are quite simple.)

-- Michael Fraser (, September 23, 2001.

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