So, I guess there may be hope still that an adequate equivalent might be in the works? Some of us still really love the creamy smooth look of 1:0 and don't mind the speed loss, I for one actually welcome it shooting in bright sun.
Patiently waiting impatiently. BTW, happy new year to everyone.Bill Troop and I are in constant communication trying to resolve this from patents and information I have.
Please bear with us.
PE
I've been reading about another of the super fine grain developers, Edwal Super 20. Here is a quote from The Compact Photo Lab Index:
Edwal Super 20
For Extreme Fine Grain
Edwal Super 20 is a true "super fine" grain developer, meaning that it will consistently produce negatives capable of 15 to 25 diameter enlargements from coarse grain films, 20 to 30 diameters or more from medium grain films, and practically unlimited enlargements when used with fine grain films.
For comparison, its companion developer, Edwal FG7, is a "fin grain" (not super fine grain) developer, capable of 10 to 15 diameter enlargements from coarse grain, high speed films.
After a little digging and some confusion over the mysterious "Gradol" in the formula I came across this:
Distilled water 750 ml
Gradol (derivative of para aminophenol) 5 gr
Fine Grain Sulphite (Sodium sulfite anhydrous) 90 gr
Diamine-P (paraphenylenediamine) 10 gr
Monazol (Glycin) 5 gr
Water to make 1.0 L
The liquid commercial version of this formula was known as Edwal Super 20
This Edwal formula is from 1939/44. It is a staining developer with many Pyro-like qualities, but with much finer grain, better acutance and much better compensating characteristics. For many years the major stumbling block to the formula was trying to find out what "Gradol" was in the formula by Dr. Edmund Lowe (founder of Edwal). 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.
http://www.photocrack.com/photovergne_wiki/index.php/EDWAL_20
Yes, I have to agree, even Microdol-X is an early to mid 1960`s formula and B&W film emulsions have improved radically since then.However it is probably much easier now to formulate a replacement developer that would match if not out-perform Microdol-X.
Ian
I thought it was J.G. Capstaff who formulated D-76.That's the exact directions given by Ilford in their 60's Technical Sheet P10, and mirror's Kodak's use of Ammonium Chloride in the mid 1930's, the work was done by Crabtree who formulated D76.
In the early 1950's Kodak suggested a modification to Microdol to give even finer grain, by adding Benzoriazole.
Ian
US Patents have a lifespan of approximately 20 years. Microdol-X is older than that. How does Kodak keep the secrets going? My company's primary patent expired a few years ago. Nobody jumped out of the woodwork to make cheap copies.
If a company decides to lock away a product and never produce it again, the patent should expire. I also suggested that Kodak could license another company to produce the products that Kodak doesn't see fit to make.
I believe that manufacturers also reserve the right to modify their formulae if it improves the performance, so some developers might have had certain components replaced over a long time span since they were first introduced.Brad;
You are exactly correct! It is what is called a "Trade Secret".
PE
I thought it was J.G. Capstaff who formulated D-76.
Those images seem to have good sharpness and tone graduation. Could you check your book to confirm the 40 grams of ammonium-chloride to each litre of D-76 stock-solution?nworth mentions the use of ammonium chloride as an additive to a developer. I've done that, after coming across a reference to this technique in a mid-50's Nikon rangefinder handbook, in developing tables in the back of the book. That book is in storage at the moment, but I recollect that one was told to add 40 grams of ammonium chloride to one liter of D-76 (I'm pretty sure about the 40 grams, less so that it was to one liter -- but it seems reasonable). Halve the ISO you shoot at and double the development time.
I'm attaching two photos I took using this developer. It seems to produce creamy images, though not unsharp. When looking at the emulsion side of the film when dry, it did seem to have a sheen to it that may in fact have been the re-deposited silver that the use of ammonium chloride is supposed to produce.
The bicycle shot is on TMAX 400, taken with an 85mm f/1.7 Rokkor wide open. and I believe the clown head is on Arista 400 (reported to be re-badged Tri-X) taken with a Leica M2 and perhaps a Canon 35mm f/2 or Canon 50mm f/1.5 lens.
Patent lifespan
In Canada, a patent lasts 20 years from the date of application, for applications filed since 1 October 1989. In the United States, the term is also 20 years from the date of the first filed U.S. application; however, for applications filed since 29 May 2000, the term may be extended based on any delays in issuance of the patent caused by the U.S. Patent and Trademark Office.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?