Module roll 

A roll: one photograph, one decode, five developments and a proof.

The bench used to ask the model six times — five prints and a proof — and each of those calls decoded the photograph again. It was the largest single cost of making a roll, and it bought nothing: the negative is the same negative at every development time. This module is that knowledge in one place: read the file once, develop it five ways, print the proof, write the lot.

Structs

RollOutcome

What a roll produced.

RollRequest

What a roll is asked for.

Enums

Progress

Where a roll has got to.

Functions

roll

Develop a photograph into a roll: one read, five prints, one proof.