D-23 has only 2 ingredients but produces clean negatives with fine grain, excellent tonal separation and good film speed. D-23 is a "general purpose" formula.
D-23 is so easy to make, you can mix it fresh from powder every time! Use it once and discard it.
Try D-23 diluted 1:1. It's even cheaper that way and longer developing times give us better control when performing Development By Inspection - or when handling many sheets at once.
D-23 is a one-bath developer. It is not the same as Divided D-23, a 2-bath formula. Divided D-23 is also known as DD-23. Divided D-23 is a "compensating" formula used to handle scenes of high contrast.
Are you looking for Divided D-23 ? See this article.
D-23 is not perfect. Other developers may offer modest improvements in grain or acutance or film speed - but there are few developers that are as simple and easy to prepare. With large format film what matters most is tonality and ease of control.
D-23 hasn't been offered as a commercial product for decades - but keep in mind that manufacturers sell formulas that are profitable. They often modify formulas to give them longer shelf-life in the store, or make them cheaper and easier to manufacture on an industrial scale.
In the limited BTZS testing I performed, the effective film speed and contrast curves obtained with D-23 diluted 1:1 were virtually identical to those of other popular developers like D-76 1:1 and Pyrocat HD 1:1:100.
If we make huge prints, shoot very contrasty subjects, print with UV light or want exaggerated acutance, we may require special-purpose treatment. Otherwise, we are free to consider general-purpose formulas and secondary factors like simplicity, cost and toxicity. In that case, D-23 is an attractive option.
You might find it interesting to read this thread on Photrio which discusses the remarkable similarity of D-23 to the classic fine-grain developers Kodak Microdol-X and Ilford Perceptol. Apparently a dash of salt is the only difference. Of course in Chemistry, a dash of this or that can make a big difference: does a dash of salt provide better storage life ? sharpness ? acutance ? tonality ? Or does it merely change the formula for the purpose of intellectual property ?
You can read more about this formula in the 1949 book Kodak Chemicals And Formulae. See page 12.
This famous 1944 Ansel Adams photograph was developed in D-23. You can purchase a copy of it from the Ansel Adams Store. Mr. Adams describes it in Examples: The Making of 40 Photographs, pp. 164: "I used my 8x10 Ansco view camera with the 23-inch component of my Cooke Series XV lens with a Wratten No. 15 (G) filter. The film was Isopan, developed in Kodak D-23."
Here are a few interesting quotes concerning D-23 from The Darkroom Cookbook, by Stephen Anchell:
"Developers are made up of four basic components:
All four of these components are necessary for the development process to be successful. Often, however, one chemical will serve more than one function. For example, Sodium Sulfite is usually used as a preservative to prevent oxidation. In the film developing formula Kodak D-23 the large amount of Sodium Sulfite (100 grams) serves to create an environment sufficiently alkaline that the developing agent, Metol, can reduce the Silver Halide without an additional accelerator. As development proceeds, soluble Bromide is precipitated out of the film, acting as an effective restrainer. D-23 has only two chemicals - Metol and Sodium Sulfite - yet as a developer it has all four of the required components" - pp. 40
Anchell mentions that many general-purpose developers contain 2 developing agents, like D-76 which uses Metol and Hyrdoquinone: the two agents work faster together. This is known as Superadditivity. However....
"Kodak D-23 This is a semi-compensating developer that produces fine shadow values while retaining a high emulsion speed... Note: This developer produces negatives of speed and graininess comparable to Kodak D-76, without D-76's tendency to block highlights. " - pp. 150
When you mix your chemistry fresh every time, there's no danger of stock solution going bad on the shelf. If you've ever had the experience of using expired chemicals, you'll appreciate this point.
|Ingredient||Full Strength||1:1 Dilution|
|Metol||7.5 g||3.75 g|
|Sodium Sulfite||100 g||50 g|
|Water to make||1 Liter||1 Liter|
Developing times for D-23 are similar to those of D-76. For normal treatment, I develop Kodak TMAX 400 and Ilford HP5+ for around 9 minutes in D-23 1:1 at 70 degrees Fahrenheit (21 degrees Celsius), using tray development with the shuffle method. I usually process 5 to 12 sheets at a time: agitation is not continuous but frequent.
In the USA, a good source for materials is Artcraft Chemicals.
Note: The appealing tonality in these sample images is not due to D-23, which is merely a simple and convenient general-purpose developer. The Ansel Adams photograph above demonstrates that for good tonality, we need an attractive subject and favorable lighting. With those prerequisites in place, only routine exposure and processing are required.