Instant Mytol is a DIY film developer that produces results virtually identical to XTOL, but can be mixed up in much smaller quantities, stored dry for unlimited shelf life, and costs less since the ingredients are generally cheap and available. You can expect full box speed or better, very low grain, excellent sharpness, and a straight tone curve.

This capsule is sized to hold exactly enough dry ingredients to make 250ml of stock strength Instant Mytol developer (equivalent to stock-strength XTOL). Mytol can also be used 1:1. I keep 6 of these capsules in my darkroom and refill all of them in a batch when all 6 are empty. The lid is designed to be screwed underneath a shelf if desired. I have had no issues printing it from PLA, though PETG or ABS would probably also be fine.

Note that one ingredient (Phenidone) is used in such a small quantity for a single “dose” of the developer that I recommend making up a 2.5% solution in propylene glycol (this will last essentially forever without going bad). That can then be easily measured with the needed precision. A finished “capsule” includes all the alkali powders in one chamber, all the non-alkali in the other, and a tiny glass vial of Phenidone solution in the center. All of this can be dumped into 250ml of distilled water, stirred up until dissolved, and warmed to normal developing temp (68°F or 20°C) before immediate use, then discarded after developing. Use the same times you would for XTOL stock.

Pictured in the photo is a scanned frame of 35mm HP5+ shot at box speed and developed in Mytol.

Recipe: