JOBO Alpha is a two-part liquid developer for black and white film, two 300 ml bottles.
What it is for
A developer from a maker of processing equipment, built for volume: six litres of working solution and some fifty films from one box. This is for someone who develops in batches — in a rotary processor, or simply regularly rather than once a season.
How to dilute it
The two bottles make 6 litres of working solution, enough for about 50 films.
The solution is replenishable — kept and reused, with development time extended as it exhausts. Keep count of the films put through it; that is the only way to avoid an underdeveloped roll at the end of its life.
Storage
Sealed concentrate keeps well but dislikes air: the emptier the bottle, the faster it oxidises. Decant the remainder into a smaller bottle, or displace the air — that is what gets a concentrate to its last measure.
How it compares
On cost per frame this is among the cheapest options in the catalogue. If you develop rarely, buy a smaller concentrate — six litres of working solution still has to be used up in time.
