Black & white film development
This guide covers the step-by-step process of developing black & white film. The process consists of three main stages: developing, stopping, and fixing.
1. Develop
The first step is to develop the film, turning the latent image into a visible negative.
This is done by converting the exposed silver halide crystals into metallic silver. The metallic silver absorbs light and appears black, creating a negative of the light areas of the scene.
Light exposure & density
- Areas that received more light become denser with metallic silver.
- Areas that received no light remain as silver halides, which will be removed later.
Development time & temperature
Development time depends on:
- The type of developer used (strength & formula).
- The temperature of the chemicals.
- The film stock being developed.
Note:
Since different films have unique development times, mixing different emulsions in the same tank is usually not recommended.
Recommended developing times
- Manufacturer recommendations
Many film boxes include a table with development times for common developers. Major brands like Ilford provide online processing guides.
- Film developing calculator
Our film developing calculator provides precise times for a wide range of film & developer combinations. It also adjusts for temperature variations and optimizes for rotary processors, speed, or grain structure.
- Estimating development time manually
If no official time is available, you can perform a development test.
Adjusting for temperature
Most development times are based on a standard 20°C solution temperature. However, temperature adjustments may be necessary.
- Measure the temperature of your developer.
- Adjust your time using a compensation chart.
- Ilford provides a time compensation chart for minor temperature variations.
Tip:
Our black & white film developing time calculator will adjust the developing times based on the given temperature, and even warn you when your developer may be too hot!
Agitation technique
Regular agitation ensures even development by moving fresh chemistry over the film surface.
Standard tank development:
- Invert the tank for 15 seconds every minute.
- No adjustment to development time is needed.
Rotary processors:
- Agitation speeds up development and can lead to increased contrast if excessive.
- When using continuous rotary processors, reduce development time by 15%.
2. Stop
Once development is complete, the process must be stopped immediately to prevent overdevelopment. This is done using a stop bath or water rinse. Stop bath is often a citric acid solution which lowers the pH, halting development and extending the life of the fixer by reducing contamination.
Stop time & temperature
- Standard time: 1 minute for fresh stop bath
- Required temperature: similar to developer
- Agitation: Continuous or 10 seconds every 30 seconds
Alternatively if no stop bath is available, multiple rinses of clean water can be used.
3. Fix
Fixing removes unexposed silver halide crystals from the film, making the negative stable and light-safe. If the film is exposed to light before being fixed, the remaining silver halides will become exposed. This appears as a cloudy fog in the clear areas of the negative.
Fix time & temperature
- Standard time: 5–7 minutes, depending on the fixer’s strength
- Required temperature: similar to developer
- Agitation: Continuous or 10 seconds every 30 seconds
If fogging appears after fixing, the negatives can be re-fixed to clear the remaining halides.