Edwal 20 and Gardol is it Pyro?

Paul Howell · Sep 19, 2016

I found on the top shelf of my bookcase my copy of Champlin on Fine Grain and the formula for Edwal 20:

Water 1 liter
Gradol 5 grams
Paraphenylendiamine 10 grams
Sodium Sulphite 90 grams
Glycin 5 grams

Champlin used Rubinol from DuPont (Fefender) in several of his formulas which he later substitutes with Pryo. I wondered if Gradol is just another trade version of Pyro. I had to dig through my negatives until I found a set I had developed in Edwal 20, 1966 and it has a light stain. I was going to mix a test batch until I found that a Pryo is $95 for 10 grams, I am curious but not $100 curious. I do have some Catechol so might try Edwal 20 formula and use 17 grams of Catechol for Gradol. MCM 100 uses Catechol but is a much different formula that Edwal 20.

John Wiegerink · Sep 19, 2016

I read the heading and it said Gardol and I scratched my head. I think Gradol is Para-Aminophenol or something close to it. Gradol was just the companies name of the chemical. Like Kodalk and balanced alkali/sodium metaborate.

Gerald C Koch · Sep 19, 2016

Gradol is p-aminophenol hemisulfate. You can substitute the hydrochloride salt if the make adjustment for the differing molecular weight.

Dr Edmund Lowe, the founder of Edwal products did not think very much of Champlin and his book. He described the book as "Champlin tracks the dragon grain to its lair and smothers it in clouds of nickel ammonium sulfate." The book is pure drivel and worth reading only for fun if you understand the awful chemical errors that Champlin makes. He was not a chemist and did not have even a passing understanding of chemistry. Interestingly Lowe did like Champlin 17 which did not appear in the book but in a later magazine article. Formula 17 does appear in Lowe's book and is said by some to be the basis for FG-7. Unfortunately one of the ingredients chlorohydroquinone is not readily available anymore.

Paul Howell · Sep 19, 2016

As I am moving away from MCM 100 due to cost, unlikely I will attempt experiment with any of the formulas, it is interesting that Champlin mentioned Champlin 17 in On Fine Grain but did not did did not provide the formula. I used Edwal 20 until it was withdrawn from the market at which time I used FG7 for several years.

John Wiegerink · Sep 19, 2016

Paul,
You could probably make your own MCM 100. I made an excellent batch of Edwal 12 replacing Paraphenylendiamine with "color developer CD-2". You could try that and compare the results to your beloved and rightfully so, MCM 100. I have used MCM 100 a couple of times and was intrigued by the look of the emulsion side of the film. Very shiny with a slight etching and very crisp prints too.

Paul Howell · Sep 19, 2016

I have the formula for MMC 100, Catechol is somewhat expensive $45 for 10 grams, MCM 100 calls for 9 grams for 1 liter. It is still cheaper to buy the PF kit, but a gallon is around $48.00. Pryo is running $95 for 10 grams. Edwal 12 uses Methol, home made Edwal 12 is within my price range and I might keep some on hand for low contrast scenes, most likely return to D76 as my primary developer or make up Ansco 17. (I just found 100 grams for $26 so I will likely mix my own MCM 100)

John Wiegerink · Sep 19, 2016

Paul Howell said:
I have the formula for MMC 100, Catechol is somewhat expensive $45 for 10 grams, MCM 100 calls for 9 grams for 1 liter. It is still cheaper to buy the PF kit, but a gallon is around $48.00. Pryo is running $95 for 10 grams. Edwal 12 uses Methol, home made Edwal 12 is within my price range and I might keep some on hand for low contrast scenes, most likely return to D76 as my primary developer or make up Ansco 17. (I just found 100 grams for $26 so I will likely mix my own MCM 100)

Paul,

Where are you buying your Catechol or pyrocatechin from? That price is in outer space. Photographers Formulary has 1lb. for 45.95.

Gerald C Koch · Sep 19, 2016

Just my personal comment. All the really old developers that contain paraphenylenediamine were developed at a time when 35mm film had really coarse grain. With today's modern fine grain films the use of these developers seems rather pointless.

Paraphenylenediamine can cause severe skin irritation and also cross sensitization to other chemicals. I developed a severe allergic reaction to one of the color developing agents based on PAP. I can no longer do any color processing.

In addition PAP can cause dichroic fog with some emulsions. If you are looking for finer grain you might consider something like Microdol-X or Perceptol. Here fine grain is obtained from a high sulfite low pH developer by the addition of sodium chloride. There are substitute formulas for these developers available on APUG and the net. They should also be much cheaper to make.

http://nj.gov/health/eoh/rtkweb/documents/fs/1586.pdf

Rudeofus · Sep 20, 2016

John Wiegerink said:
Where are you buying your Catechol or pyrocatechin from? That price is in outer space. Photographers Formulary has 1lb. for 45.95.

+1 to this. Interestingly, these numbers (45.95 and 98.00) do show up on photo formulary's page, however, these prices do refer to the 1lb batch. Is there a chance, that a script blocker interferes with Paul's view of this page?

Paul Howell · Sep 20, 2016

Your right, I though the 1 pound was 10 grams.

Edwal 20 and Gardol is it Pyro?

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