Ewesly / Holographic Formulae / Kodak D-72
(for photographic papers. A substitute for Kodak's pre-packaged Dektol.)
3 g Metol
45 g Sodium Sulfite
12 g Hydroquinone
80 g Sodium Carbonate (Monohydrated)
2 g Potassium Bromide
One litre of water
Working strength solution: Dilute one part of developer with two parts water.
one and a half minutes for fiber-based papers, one minute for the resin-coated kind.
Temperature: 20C +- 1C Agitation: Constant
Shelf life: Stock solution in a stoppered bottle 6 months; working solution in a tray, overnight.
Photo Lab Index, Lifetime Edition, Morgan and Morgan, Inc., Dobbs Ferry, New York.
One might wonder why a developer for photographic papers would be included in a compendium of developers for holographic films and plates. But if you compare the amounts of Metol and Hydroquinone in this brew and the amounts in the venerable Kodak D-19, you can get the same proportions of the developing agents by diluting two parts of the D-72 stock solution with one part of water. (Sort of the opposite proportion when using this developer for its intended application, photographic paper.) The Sodium Carbonate quantities are similar, there is less Sodium Sulfite present, (possibly a plus!) but there is a lot less restrainer (Potassium Bromide). (Jury's out on that one!)
Why this early 20th century photographic formula is important to the 21st century holographers is that this formula works identically to Kodak’s proprietary paper developer, Dektol. I have never encountered the Dektol formula in print, but it must be close to this one in its contents, as prints developed in D-72 need the same exposure and exhibit the same contrast as those developed in Dektol.
So if you can find a package of Dektol in a camera store, mix it up and dilute it two parts Dektol to one part water and Voila! D-19 substitute!