Film development timer

Pick a film, a developer and dilution, the EI you exposed it at, and the developer’s temperature: the page gives the development time with where it came from — the datasheet’s own number, Kodak’s time/temperature table, or Ilford’s time/temperature chart. Then send it to the Process timer, which walks you through the whole process with a big countdown and tells you when to agitate.

How to use it

Time — the result card shows the time to the second and as a datasheet would print it (to ¼ minute). At other temperatures lists the time from 18 to 24 °C (Kodak films: at the 65, 68, 70, 72 and 75 °F columns of Kodak’s own table). Push and pull lists every EI the datasheet gives a time for; tap one to use it. EIs between two published ones are interpolated (marked) and EIs outside them have no time.
Temperature — °C or °F, remembered for all the photography tools.
Agitation — intermittent (inversions in a spiral tank, which the times assume) or continuous (rotary processor, dish). Ilford says to cut its times by up to 15 % for continuous agitation; the page takes the full 15 %.
Process timer — pick black and white (the time from the Time tab), C-41 or E-6. Each step shows its agitation pattern, which you can change; edit any time (7:30, 7.5 or 450s), rename, reorder, add or remove steps. Start runs it: the badge says when to agitate and when to rest, beeps and vibrates (on phones that can) at each agitation, Drain now 10 s before the developer ends, and a chime at each new step. Manual steps (the Ilford wash, pre-warming) wait for Next. The screen stays on while it runs. ⛶ Full screen (or F) makes the countdown fill the screen; Esc leaves.
Pre-soak and wash — a 1-minute water pre-soak is optional (Ilford advises against a pre-rinse in rotary processors). The wash is Ilford’s method for non-hardening fixers (fill and invert 5 times, then 10, then 20) or running water.
My combos — add films and developers the page doesn’t have (from their current datasheet or your own tests): the time at a temperature, and other temperatures follow Ilford’s chart. They stay in this browser; Export JSON and Import JSON move them between devices.

Where the numbers come from

Every built-in time is transcribed from a manufacturer’s datasheet:

ILFORD HP5 Plus technical information (April 2010) — Ilford developers and the Kodak and Agfa developers Ilford lists (D-76, HC-110, XTOL, T-MAX, Rodinal).
ILFORD DELTA 100 Professional (May 2010) and DELTA 400 Professional (May 2010) technical information.
ILFORD liquid film developers — ILFOTEC DD-X, ILFOTEC LC29, ILFOSOL S (June 2010): the FP4 Plus times.
KODAK PROFESSIONAL TRI-X 320 and 400 Films, F-4017; T-MAX 400 Film, F-4043; T-MAX 100 Film, F-4016 (all February 2016): the small-tank tables, agitation every 30 s.
KODAK Color Negative C-41 Film Processing Kit instructions (2024): developer 3:15 at 37–39 °C, bleach 6:30, wash 1:30, fixer 6:30, wash 3:15, final rinse 1:30, with the kit’s agitation pattern for each.
Kodak’s six-bath E-6 process (publication Z-119): first developer 6:00, first wash 2:00, reversal bath 2:00, colour developer 6:00, pre-bleach 2:00, bleach 6:00, fixer 4:00, final wash 4:00, final rinse 1:00.

Temperature. For Kodak films the page interpolates Kodak’s table (on a log-time scale) between its columns. Ilford sheets give one time at 20 °C and a time/temperature chart whose worked example is 4 minutes at 20 °C → 3 minutes at 23 °C and 6 minutes at 16 °C; the page uses the straight line through both points on a log-time scale, about 10 % per degree (log₁₀(t/t₂₀) = −0.0432 × (T − 20)).

Agitation. Ilford: invert the tank four times in the first 10 seconds, and four times in the first 10 seconds of each following minute, tapping the tank after each. Kodak: 5–7 inversions in 5 seconds at the start, repeated every 30 seconds.

For combinations not here, the Massive Dev Chart (digitaltruth.com) collects times from many sources, including users' own; nothing from it is copied here. Check its source column, and prefer the manufacturer’s current datasheet.

Limits

Ilford’s current sheets. These are the editions available to transcribe; Ilford revises them, and ILFOSOL S has since been replaced by ILFOSOL 3, whose times differ. Check the current sheet on ilfordphoto.com, and add ILFOSOL 3 or any updated time under My combos.
Push times exist only where the sheet gives them. Interpolated EIs are an estimate between published points; test a roll.
Kodak’s push tables for T-MAX films give times only at 68 °F and 75 °F; other temperatures are interpolated between those two.
Development times are starting points (both makers say so): your water, thermometer, agitation and enlarger or scanner all move them. Times under 5 minutes may develop unevenly.
Colour processes are temperature-critical. The timer doesn’t measure temperature; keep the tank and bottles in a water bath at 38 °C.
Sound needs a tap first on most phones; vibration works only where the browser supports it (not on iPhones). Keep the page in front while it runs.

Related: exposure calculator (reciprocity failure for film), timers (general countdowns and intervals), night-sky photography, print size and DPI.

Linking to an example

Share link copies a URL that opens the tool with your settings (your own combinations are not included). Links can also be written by hand; put the tab after #: time, process or combos. Temperatures in links are always in °C.

Parameter Meaning Example

Parameter	Meaning	Example
`film`	Film: `hp5`, `fp4`, `delta100`, `delta400`, `trix`, `tmax400`, `tmax100`	`film=hp5`
`dev`	Combination: film/developer/dilution, as in the presets below	`dev=hp5/ddx/1-4`
`ei`	Exposure index	`ei=1600`
`temp`	Developer temperature, °C	`temp=22`
`agit`	Agitation: `intermittent` or `continuous`	`agit=continuous`
`process`	Process timer: `bw`, `c41` or `e6`	`process=c41`
`presoak`	Add a 1-minute pre-soak (`true` / `false`)	`presoak=true`
`wash`	Wash: `ilford` or `running`	`wash=running`
`example`	One of the presets below; parameters given with it override the preset’s	`example=hp5-ddx`

film

Film: hp5, fp4, delta100, delta400, trix, tmax400, tmax100

film=hp5

dev

Combination: film/developer/dilution, as in the presets below

dev=hp5/ddx/1-4

ei

Exposure index

ei=1600

temp

Developer temperature, °C

temp=22

agit

Agitation: intermittent or continuous

agit=continuous

process

Process timer: bw, c41 or e6

process=c41

presoak

Add a 1-minute pre-soak (true / false)

presoak=true

wash

Wash: ilford or running

wash=running

example

One of the presets below; parameters given with it override the preset’s

example=hp5-ddx

Developers in combination ids: ddx, ilfosol-s, id11, microphen, ilfotec-hc, lc29, rodinal, d76, hc110, xtol, tmaxdev; dilutions are written 1-4, 1-1, stock, b.

Presets:

example= Shows

`example=`	Shows
`hp5-ddx`	HP5 Plus at box speed in DD-X 1+4: 9 min at 20 °C (open)
`hp5-push-1600`	HP5 Plus pushed two stops to EI 1600 in ID-11 stock: 14 min (open)
`trix-d76-22c`	TRI-X 400 in D-76 stock at 72 °F: 5½ min, from Kodak’s table (open)
`delta400-warm`	DELTA 400 in DD-X at 23 °C: Ilford’s chart shortens 8 min to about 6 min (open)
`c41`	The C-41 colour negative process from Kodak’s kit (open)
`e6`	The E-6 six-bath slide process (open)

hp5-ddx

HP5 Plus at box speed in DD-X 1+4: 9 min at 20 °C (open)

hp5-push-1600

HP5 Plus pushed two stops to EI 1600 in ID-11 stock: 14 min (open)

trix-d76-22c

TRI-X 400 in D-76 stock at 72 °F: 5½ min, from Kodak’s table (open)

delta400-warm

DELTA 400 in DD-X at 23 °C: Ilford’s chart shortens 8 min to about 6 min (open)

c41

The C-41 colour negative process from Kodak’s kit (open)

e6

The E-6 six-bath slide process (open)