A concentrated developer formula similar to Rodinal.

Read the following instructions.
Sodium bisulfite50grams
Para-aminophenol Hydrochloride30

When solution is complete, filter and add with vigorous stirring a solution of 1 part sodium hydroxide in 5 parts water until the solid which first forms is just re-dissolved. Dilute to 1 liter and store in small full bottles.

This developer is supposed to give exactly the same results as Rodinal. Actually it does not. The formula yields a solution having a pH of approximately 11.7, whereas Rodinal shows a pH of 12.3. In practice, the presented formula is softer working than commercial Rodinal and requires 20–30% more developing time to give the same contrast. If potassium hydroxide is used instead of sodium hydroxide a solution having a pH of 12.1 is obtained which is more similar to Rodinal.

To use, dilute 1:10 and develop the negatives in a tray for 5–7 minutes at 18.5°C. For softer negatives dilute 1:20 and develop for 8–12 minutes. For tank development, dilute 1:30 and develop for 25–35 minutes, depending on the contrast desired.

Note: Negatives will lose density in the fixing bath and development should be carried further than usual.