Stop Bath and Fixer Timer

Running order

1.Stop bath 00:30
2.Fixer 05:00
3.Wash 10:00

Total 15:30 across 3 steps.

After development, the stop bath halts development quickly and the fixer removes undeveloped silver halide, making the image permanent and safe in light. Stop bath is around thirty seconds; fixer is five to ten minutes depending on the fixer type and whether it is film or paper.

Fixing time is the step where under-doing it causes damage that appears months or years later, as staining and fading. Over-fixing is also possible with paper, where prolonged fixing bleaches faint highlight detail and makes washing harder, so the range matters in both directions.

The clip test tells you when fixer is exhausted

Drop a scrap of undeveloped film leader into the fixer and time how long it takes to clear. Fresh fixer clears film in a minute or two; fixer taking twice as long as it did when fresh is exhausted and should be replaced.

The conventional rule is to fix for twice the clearing time. That is a self-adjusting figure rather than a fixed one, and it means the same procedure keeps working as fixer ages up to the point where it should be discarded.

Washing determines whether prints survive

Residual fixer left in a print is the main cause of long-term staining and fading. Fibre-based paper holds fixer in the paper base and needs far longer washing than resin-coated paper, which only has to release it from the surface.

A hypo clearing agent between fixer and wash substantially shortens the required wash time for fibre paper and reduces water use. For anything intended to last, it is worth the extra step.

Order and contamination

Fixer carried back into developer ruins the developer, which is why the stop bath sits between them and why tongs are kept to their own trays. A single pair of tongs used across all three trays is the classic way to contaminate a whole session.

Stop bath also extends fixer life by preventing developer carryover from neutralising the fixer's acidity. Water works as a stop in a pinch and does neither job as well.

Typical figures at 20 °C. Fix for twice the clip test clearing time; wash times differ sharply by paper type.

Stop, fix and wash times
Step	Film	RC paper	Fibre paper
Stop bath	30 s	10–30 s	10–30 s
Fixer (rapid)	2–5 min	1–2 min	1–2 min
Fixer (standard)	5–10 min	5–10 min	5–10 min
Hypo clearing agent	1–2 min	—	2–3 min
Wash	5–10 min	4 min	20–60 min
Wash with clearing agent	5 min	2 min	10–20 min

Clip test: fresh fixer clears film leader in 1–2 minutes. Fix for twice the clearing time; replace when it takes double the fresh figure.
Residual fixer is the main cause of long-term staining. Keep tongs to their own trays — fixer in developer ruins the developer.

Source: Stop, fix and wash times are established darkroom convention; specific chemistry instructions are authoritative

Sources

Stop, fix and wash times are established darkroom convention; specific chemistry instructions are authoritative , TheTimerLab — accessed 2026-07-28

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❓ Frequently Asked Questions

How long is stop bath?

Around thirty seconds for film and ten to thirty for paper. Its job is halting development quickly and protecting the fixer from developer carryover.

How long should I fix for?

Twice the clip test clearing time — commonly two to five minutes for rapid fixer and five to ten for standard. Under-fixing causes staining that appears months or years later.

What is the clip test?

Dropping a scrap of undeveloped film leader into the fixer and timing how long it takes to clear. Fresh fixer clears in a minute or two; double that means the fixer is exhausted.

Can I over-fix?

With paper, yes. Prolonged fixing bleaches faint highlight detail and makes washing harder, so the range matters in both directions rather than only as a minimum.

Why do fibre prints need such long washing?

Because fixer soaks into the paper base rather than sitting on a surface. Resin-coated paper washes in a few minutes; fibre can need twenty to sixty without a clearing agent.

Is a hypo clearing agent worth using?

For anything intended to last, yes. It substantially shortens the required wash for fibre paper and reduces water use, and residual fixer is the main cause of long-term fading.