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Edwal "Modern Developing Methods"

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Thanks!!

Interesting read ... the Edwal 10 formula listed is quite different than the one I found on Photrio.
 
Alan Johnson said:
Thanks. I note from p129 that Diamine-P is p-phenylenediamine and Monazol is glycin.
I hope to make some Edwal 12 (p30) sometime to compare with Jay DeFehr's Halcyon I made and used up.
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That will be quite interesting, Alan! Are you getting glycin in Europe from Suvatlar? Just wondering. Also wondering about a source for PPD. Or are you substituting something like CD3?
 
I ordered glycin from Photoformulary but they cannot ship PPD outside US I believe. I was told Suvatlar have PPD in Europe.
By my tests it is a waste of time to try CD4 it just does not have the fine grain solvent action of PPD.
 
relistan said:
Found this on archive.org and thought I'd share it. Has a lot of general information, but contains some formulas and other info on Edwal developers and other chemistry: https://ia800202.us.archive.org/7/items/ModernDevelopingMethods/Edwal - Modern developing methods (1947).pdf

3rd Edition, Sixth printhing: March 1947
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This is a nice book with a lot of useful information. On page 32 it has a picture of a chapel which according to the book "was made by Dr. E. W. Lowe in 1932 from a negative on the first full roll of film ever developed in Edwal-12". Does this mean that Dr. Lowe didn't develop full rolls of film with intermediate versions of his developer? :smile:
 
Raghu Kuvempunagar said:
This is a nice book with a lot of useful information. On page 32 it has a picture of a chapel which according to the book "was made by Dr. E. W. Lowe in 1932 from a negative on the first full roll of film ever developed in Edwal-12". Does this mean that Dr. Lowe didn't develop full rolls of film with intermediate versions of his developer? :smile:
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You're right there is a lot of good info in there. Some interesting chemistry, too.

Re: full rolls. I would guess that's what it means. I don't develop full rolls when experimenting. I just shoot a few frames of 35mm and then snip them out of the camera. Probably he did the same. :smile:
 
It is possible to open a free web archive account ,borrow and read "What you want to know about developers, fine grain and otherwise" by Edmund W Lowe here:
https://archive.org/details/whatyouwanttokno00lowe/mode/1up?view=theater
Edwal 12 starts on p89 and there are photomicrographs showing the granularity obtained with various developers of the 1939 era on p102-106
Searching Photrio one may find a number of posts by Gerald Koch cautioning about the hazards of using PPD.
 
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Has anyone attempted Edwal 20. I used it a couple of times in college, shot 60s vintage GAF 500 at 200, very nice grain, otherwise hated GAF 500.
 
My Oh My how time flies, forgot I asked about Gardol, at one point I did email the current owners of Edwal who never got back to me.
 
So, can it be used just like Gardol, in terms of same amount of p-aminophenol for Gardol or it does it need to be further refined to become Gardol?
 
Paul Howell said:
So, can it be used just like Gardol, in terms of same amount of p-aminophenol for Gardol or it does it need to be further refined to become Gardol?
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In that other thread Gerald Koch suggested calculating the molecular weights and adjusting accordingly: "You can substitute the hydrochloride salt if the make adjustment for the differing molecular weight." I can't find the hemisulfate he describes but it looks like p-aminophenol sulfate has a molecular weight of 207.21 g/mol. vs p-aminophenol hydrochloride is 145.59 g/mol .

If he's right about the substitution, and he meant sulfate, then you'd use 70% as much p-aminophenol hydrochloride, so 3.5g p-aminophenol hydrochloride according to the formula you posted. Hopefully someone like @Alan Johnson can tell me if I'm off about either of those things.

mshchem said:
I have my Dad's copy, pre-war I believe.
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Very cool!
 
The prewet debate. Edwal calls for a 2 to 3 minute soak to relax the film and prevent air bells. 1939!
 
relistan said:
In that other thread Gerald Koch suggested calculating the molecular weights and adjusting accordingly: "You can substitute the hydrochloride salt if the make adjustment for the differing molecular weight." I can't find the hemisulfate he describes but it looks like p-aminophenol sulfate has a molecular weight of 207.21 g/mol. vs p-aminophenol hydrochloride is 145.59 g/mol .

If he's right about the substitution, and he meant sulfate, then you'd use 70% as much p-aminophenol hydrochloride, so 3.5g p-aminophenol hydrochloride according to the formula you posted. Hopefully someone like @Alan Johnson can tell me if I'm off about either of those things.


Very cool!
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I found my Dad's copy, 3rd edition April 1945. My Mother gave it to my Dad January of 1946, this was their 2nd anniversary. They got married off the Navy base he was assigned right before going to support the big push in the Pacific Theater WWII.
Crazy world, I sit surrounded by Japan and German made photo equipment :smile:. I'm glad we have that behind us. :heart:
 
relistan said:
In that other thread Gerald Koch suggested calculating the molecular weights and adjusting accordingly: "You can substitute the hydrochloride salt if the make adjustment for the differing molecular weight." I can't find the hemisulfate he describes but it looks like p-aminophenol sulfate has a molecular weight of 207.21 g/mol. vs p-aminophenol hydrochloride is 145.59 g/mol .

If he's right about the substitution, and he meant sulfate, then you'd use 70% as much p-aminophenol hydrochloride, so 3.5g p-aminophenol hydrochloride according to the formula you posted. Hopefully someone like @Alan Johnson can tell me if I'm off about either of those things.


Very cool!
Click to expand...

I might order p-aminophenol, I have the other chem stashed and mix a liter to see how well it works. Saying that, gain is so much finer with modern films than GAF 500 I'm not sure what the value will be. Foma 400 at 200 or 100, might be worth a try.
 
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Paul Howell said:
I might order p-aminophenol, I have the other chem stashed and mix a liter to see how well it works. Saying that, gain is so much finer with modern films than GAF 500 I'm not sure what the value will be. Foma 400 at 200 or 100, might be worth a try.
Click to expand...

If you do, please post back, I'd hear to see the results.
 
Hey @Paul Howell, I found a different link where Gerald explained in more detail: https://www.photo.net/discuss/threads/edwal-super-20-formula.83786/#post-964934

Gradol is the hemisulfate of p-aminophenol C6H7NO.1/2H2SO4 and has a molecular weight of 158.14. You can substitute p-aminophenol hydrochloride for the Gradol, use 0.9X of the amount called for. No need to make any other adjustments. Do not add sulfuric acid or any other sulfate to the developer.

That's a different molecular weight than the sulfate. So I'd use his 90% calculation instead of the one I did earlier. That makes 4.5g of p-aminophenol hydrochloride.
 
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