Photographers' Formulary Sodium Metaborate (Balanced Alkali, Kodalk) - 100 Grams

A Handy Bit to Have

For many users working beyond D-76 and/or attempting two-bath development this stuff is invaluable. Another use is to add a pinch (gram or so) to a gallon of distilled water before using the water to make or dilute developers. The idea was to “ionize” the water to enable better integration of solutes as you begin adding them to your developer. If you are mixing up a Metol developer for example, it’s usually suggested to add a pinch to your hot water first or the Metol will be a royal pain to get dissolved. A 2% solution is often suggested as a pre-rinse for modern 120 monochromatic emulsions to remove the antihalation dye they use in these to keep highlights sharp & clean. It works too: after a vigorous rinse for a minute or two the pouroff will be anything from a darkish purple to deep teal blue, depending on the film. You should all clean water rinses—tap water is OK—until the pouroff is clear, so the film isn’t loaded with alkali when the developer hits it and blows your highlights. Good stuff to have about!