D-72 Film Use
D-72 Film Use is the documented practice of using Dektol (D-72) paper developer for film development rather than its usual paper-developer role. D-72 on film produces dramatically high contrast — equivalent to D-19 in character — and is used for the same niche applications: copy work, document reproduction, line drawings, high-contrast astrophotography.
Key features
- Same chemistry as Dektol: vigorous MQ + sodium carbonate alkali
- Very high contrast when applied to film (films are not the intended substrate)
- Fast development: 2-4 minutes for most films
- Convenience: if you already have Dektol mixed for printing, no separate developer purchase needed
Workflow
Use 1:2 working dilution (same as Dektol's standard paper dilution) at 20°C:
| Film | Dilution | Time |
|---|---|---|
| Tri-X / HP5+ for copy work | 1:2 | 2-3 min |
| Tech Pan for line drawings | 1:2 | 2-3 min |
| Higher contrast (slides etc) | 1:1 | 1-2 min |
Practical notes
- D-72 on film is always specialty use — not for pictorial work
- Times are very short; small timing errors produce big density differences
- Continuous agitation produces more even results than intermittent agitation at these short times
- The dedicated alternative is D-19 (specifically formulated for film high-contrast)
- PPE: nitrile gloves and eye protection
Related recipes
- [[recipe-dektol-d-72|Dektol (D-72)]] — the same formula in its standard paper-developer role
- [[recipe-d-19|D-19]] — the dedicated film high-contrast developer; the recommended alternative for routine high-contrast film work
- [[recipe-pyrocat-hd|Pyrocat-HD]] — staining alternative when high contrast + compensation both matter
Mixing Instructions
Start with 750 ml of water at 52 °C (125 °F).
- Dissolve Metol first, stirring until clear.
- Add sodium sulfite and stir until dissolved.
- Add hydroquinone and stir until dissolved.
- Add sodium carbonate and stir until dissolved.
- Add potassium bromide and stir.
- Add water to make 1 liter.
This makes the stock solution. For film use, dilute 1:4 (200 ml stock + 800 ml water) at 20 °C. Use as one-shot at the diluted strength. Stock solution keeps 2-3 months in a full, tightly capped bottle.
Ingredients for 1L of Stock Solution
Volume:
ml
| # | Chemical | Role | Qty (1L) | Unit | Note |
|---|---|---|---|---|---|
| 1 | Metol | Developing Agent | 3.0 | g | (stock) |
| 2 | Sodium Sulfite | Preservative | 45.0 | g | (stock) |
| 3 | Hydroquinone | Developing Agent | 12.0 | g | (stock) |
| 4 | Sodium Carbonate | Accelerator | 80.0 | g | (stock) |
| 5 | Potassium Bromide | Restrainer | 1.9 | g | (stock) |
Process Parameters
Temp:°C
Volume:
ml
| Film Stock | ISO | Dilution | Temp | Time | Agitation | Mix (per 1L) | Source | Notes |
|---|---|---|---|---|---|---|---|---|
| Ilford HP5+ 400 | 400 | 1:4 | 20.0°C | 5:45 | Continuous first 30s, then 10s every 60s | 200ml + 800ml water | Community data | |
| Kodak Tri-X 400 | 400 | 1:4 | 20.0°C | 6:00 | Continuous first 30s, then 10s every 60s | 200ml + 800ml water | Massive Dev Chart | High contrast. Best for copy work or when maximum contrast is desired. |
| Kodak Tri-X 400 | 1600 | 1:3 | 20.0°C | 6:00 | Continuous first 30s, then 10s every 60s | 250ml + 750ml water | Community data | Push processing with undiluted-ish D-72. Extreme contrast. |