Pre-soaking and water bath techniques are simple additions to your development workflow that can improve consistency and even development. Whether you should use them depends on your films, developers, and working conditions.
What is Pre-Soaking?
Pre-soaking means filling your development tank with plain water before adding developer. The film sits in water for 1-5 minutes, then you drain and add developer as normal.
What It Does
- Wets the emulsion — Prepares the gelatin to receive developer evenly
- Removes anti-halation layer — Many films have a coloured backing that washes out
- Equalises temperature — Brings film and tank to developer temperature
- Reduces air bubbles — Wet emulsion is less likely to trap bubbles
Arguments For Pre-Soaking
Even Development
Dry emulsion can absorb developer unevenly, especially with highly concentrated developers. Pre-soaking ensures the emulsion is uniformly wet before development begins.
Temperature Consistency
If your developer is at precisely 20°C but your tank and film are at room temperature (say, 18°C), the first minute of development happens at a slightly different temperature. Pre-soaking brings everything to the same starting point.
Anti-Halation Layer Removal
Many films have a coloured anti-halation backing (often blue or green). If this layer washes into your developer, it can affect development or contaminate reused developer. Pre-soaking removes it before developer touches the film.
Bubble Prevention
The initial pour of developer onto dry film can trap tiny air bubbles against the emulsion. These bubbles block development, creating small undeveloped spots. Pre-soaking eliminates this by wetting the surface first.
Ilford specifically recommends pre-soaking their Delta films to remove the anti-halation layer before development.
Arguments Against Pre-Soaking
It's Unnecessary for Most Films
Traditional films like HP5+, Tri-X, and FP4+ were designed without assuming a pre-soak. Millions of rolls have been developed without pre-soaking with excellent results.
Can Affect Development Time
Pre-soaking swells the emulsion and can slightly alter how developer penetrates the film. Some photographers find they need to extend development time by 10-15% after pre-soaking.
Risk of Uneven Swelling
If the pre-soak water is significantly warmer or colder than the developer, thermal shock can cause uneven swelling, potentially creating development artifacts.
Added Complexity
It's one more step, one more variable, one more thing to control. If your results are good without pre-soaking, adding it may introduce inconsistency rather than eliminate it.
If you've been developing without pre-soaking and getting good results, think carefully before changing your process. Consistency matters more than optimisation.
When Pre-Soaking Helps
Pre-soaking is most beneficial in specific situations:
Modern T-Grain Films
T-grain films (like Kodak T-Max and Ilford Delta) use tabular grain technology — flat, tablet-shaped crystals rather than traditional pebble-shaped grains. They offer finer grain but can be more sensitive to development conditions.
These films benefit more from pre-soaking:
- Thicker emulsions absorb developer more slowly
- Anti-halation layers are more prominent
- Manufacturer recommendations often include pre-soaking
Highly Concentrated Developers
One-shot developers used at high dilutions (Rodinal 1+100, HC-110 at extreme dilutions) can develop unevenly on dry emulsion. Pre-soaking helps with even penetration.
Stand or Semi-Stand Development
With minimal agitation, any initial unevenness persists throughout development. Pre-soaking reduces the risk of streaks or uneven development.
Cold Working Conditions
If you're developing in a cold environment, pre-soaking at your target temperature ensures consistent starting conditions.
Very Old or Expired Film
Aged emulsions can be less predictable. Pre-soaking may help ensure even developer penetration.
The Pre-Soak Process
If you decide to pre-soak:
Fill tank with water at your development temperature (typically 20°C).
Let it sit for 1-3 minutes. Agitate gently to ensure even wetting.
Drain completely. Take your time — residual water dilutes your developer.
Pour in developer immediately. Don't let the wet film sit exposed to air.
Start timing from when developer goes in — not from when you drained the pre-soak.
If your pre-soak water turns deeply coloured (blue, green, or purple), that's the anti-halation layer. This is normal and confirms the pre-soak is doing its job.
Time Adjustments After Pre-Soaking
Some photographers extend development time when pre-soaking. The reasoning:
- Swelled emulsion may slow developer penetration
- Residual water dilutes developer slightly
- Some developers perform differently on wet vs dry emulsion
Common Adjustments
| Scenario | Time Adjustment | Notes |
|---|---|---|
| Standard films (HP5+, Tri-X) | +0-5% | Usually unnecessary |
| T-Grain films | +0-10% | Test and adjust |
| High dilution developers | +5-10% | Compensates for dilution effect |
| Stand development | No change | Already extended times |
Many photographers pre-soak without any time adjustment and get excellent results. The "required" adjustment is debated. Test with your specific film/developer combination.
Water Bath Temperature Control
Beyond pre-soaking, a water bath is essential for maintaining temperature during development, especially for temperature-critical processes like C-41 or E-6.
Why Temperature Matters
- Development rate roughly doubles for every 10°C increase
- Colour processes require ±0.3°C precision
- Even B&W benefits from consistent temperature
Setting Up a Water Bath
Choose a container — A washing up bowl, plastic tub, or cooler works well. It should be large enough to hold your chemical containers and developing tank.
Fill with water slightly warmer than your target temperature. Water in an open container loses heat to the room.
Place chemical bottles in the bath 10-15 minutes before developing. Let them equilibrate.
Keep the tank in the bath between agitation cycles. Return it immediately after each agitation.
Monitor and adjust — Add warm water as needed to maintain temperature.
Advanced: Sous Vide Temperature Control
A sous vide immersion circulator provides precise, hands-free temperature control:
- Set exact temperature (e.g., 20.0°C or 38.0°C)
- Maintains temperature indefinitely
- No manual adjustment during processing
- Especially valuable for C-41 and E-6
For B&W development at 20°C, a simple water bath is sufficient. For C-41 at 38°C, a sous vide circulator is highly recommended.
Semi-Stand and Minimal Agitation
Semi-stand development is a technique using very little agitation, falling between standard agitation and full stand development.
Semi-Stand vs Stand
| Technique | Initial Agitation | During Development | Total Time |
|---|---|---|---|
| Standard | 30 sec, then continuous | Every 30-60 sec | 6-12 min |
| Semi-Stand | 30 sec | Once at halfway | 30-60 min |
| Stand | 30 sec | None | 60-120 min |
Semi-Stand Procedure
Pour developer and agitate for the first 30 seconds.
Let tank sit completely still for half the total development time.
Single agitation — 2-3 gentle inversions at the halfway point.
Continue standing for the remaining time.
Stop, fix, and wash as normal.
When to Use Semi-Stand
- High-contrast scenes needing compensation
- When you want stand development benefits with less risk of bromide drag
- With developers that don't work well in full stand (exhaust too quickly)
Pre-Soaking for Stand/Semi-Stand
Pre-soaking is especially recommended for stand and semi-stand development because:
- Any initial unevenness persists without agitation to redistribute chemistry
- Air bubbles can cause visible marks over long development times
- Even developer penetration from the start is critical
Practical Recommendations
For Beginners
- Don't pre-soak initially — learn standard development first
- Use a basic water bath to maintain temperature
- Standardise your process before adding variables
For Consistent Results
If you decide to pre-soak:
- Always pre-soak (don't sometimes skip it)
- Use the same pre-soak duration every time
- Match pre-soak water temperature to developer temperature
- Note whether you pre-soaked in your development notes
For Problem-Solving
Consider adding pre-soaking if you experience:
- Uneven development or streaks
- Air bubble marks
- Inconsistent results with Delta or T-Max films
- Issues with highly diluted developers
Summary
Pre-soaking and water bath techniques are tools, not requirements:
- Pre-soaking helps with even development but isn't necessary for most films
- Water bath is essential for temperature-critical processes
- Semi-stand offers a middle ground between standard and stand development
- Consistency matters more than any single technique
Start simple, add complexity only when it solves a specific problem, and always change one variable at a time so you know what's affecting your results.