Film Agitation Schemes: Ilford, Kodak and Stand

Four inversions in the first ten seconds of each minute is Ilford. Five to seven inversions every thirty seconds is Kodak. They are not two ways of saying the same thing, and the version repeated all over the internet mixes them up.

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The schemes, as their makers write them

Agitate schedules agitation rather than describing it. Each scheme below is stored as a first burst, a repeat burst and the gap between the start of one burst and the start of the next, which is what a timer can actually act on.

Scheme	First burst	Then	Source
Ilford	10 s	Four inversions during the first ten seconds of each minute, then tap the tank to dislodge air bells	Manufacturer
Kodak, small tank	5 s	Five to seven inversions in five seconds, repeated every thirty seconds	Manufacturer
Kodak, large tank	15 s	Lift, drain and re-immerse the rack once a minute	Manufacturer
Continuous	Whole step	Agitate for the length of the bath	Manufacturer
Semi-stand	60 s	A single inversion every thirty minutes	Community
Stand	60 s	The tank is left alone	Community

The presets built into the app. A scheme marked community is shown as such in the interface, so a convention is never mistaken for an instruction.

There is a seventh case that matters more than any of them. Most published rows do not use a named scheme at all: the maker printed its own wording for that particular film and developer, and Agitate shows that wording verbatim on the row instead of forcing it into a preset.

Cadence	Rows
The maker's own wording, shown verbatim	420
Ilford	248
Kodak, small tank	99
Kodak, large tank	26
Stand or semi-stand	2

How the 795 published rows bundled with the app are agitated.

The Ilford scheme that is wrong everywhere

You will read, in forum posts and in app descriptions, that the Ilford method is thirty seconds of continuous agitation followed by ten seconds every minute. Ilford's own datasheets say four inversions during the first ten seconds of each minute. The thirty second cadence belongs to Kodak, and it belongs to a different burst length and a different number of inversions.

On a ten minute development that is the difference between ten agitation events and twenty, which is a visible difference in contrast. Agitate stores each scheme with its own numbers rather than one generalized cadence with a label on top, and each row carries the note the maker wrote.

Community methods keep the label on

Stand and semi-stand are in the app because people use them, and they are flagged in the interface as community practice rather than manufacturer instruction. No maker publishes a stand cadence for its developer, and pretending otherwise would be a small lie that costs somebody a roll. More on stand and semi-stand development.

A burst is not called if it cannot be completed

A scheme that repeats every minute inside a bath that has two seconds left would otherwise tell you to start agitating with two seconds to go. Agitate drops a burst that would begin at or after the end of the bath, and truncates one that would run past it. Telling somebody to invert a tank they are about to empty is worse than saying nothing.

Each burst arrives as a tap in your hand rather than as something to watch for. Sound as well, if you want it, and because the audio session is configured for playback it is audible with the ring switch on silent, which is how a phone on a darkroom bench usually sits. The scheduled alerts that survive the app going to the background are deliberately limited to the drain and the end of a bath: iOS keeps only a limited queue of pending notifications, and filling it with agitation taps would evict the one alert that actually matters.

Agitation you feel instead of count

Every scheme with its own published numbers, every row with the maker's own wording, and a burst that is never called when it cannot be finished.

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