Developer · Black and white
DIY/Homebrew Pyrocat-HD
AvailableB&WLiquid Concentrate
Also known as: Pyrocat
Sandy King's catechol-based staining developer, from the Photographers' Formulary sheet: a semi-compensating, high-definition developer made as an alternative to PMK. King cites about 1/3 stop more effective film speed, 10-15% shorter times, more consistent staining, lower toxicity and no streaking with reduced agitation. The stain is brown. Catechol is corrosive to skin and evaporates from the solid, so mix in a ventilated area.
- Type
- Liquid
- Process
- B&W
- Temperature
- 20°C
- Dilutions
- 3
- Shelf life
- Solution A about 6 months when made with phenidone; solution B not stated (Formulary sheet)
18–24°C (64–75°F)
concentrate
Characteristics
GrainFine, level 1 of 3
AcutanceVery high
ContrastCompensating
Excellent highlight separation with olive-brown stain
Dilutions
| Ratio | Use | Notes |
|---|---|---|
| 1+1+100 | One-shot | Standard working solution: 1 part A + 1 part B + 100 parts water; also the rotary-processor solution (at least 75 ml per 4x5 sheet). |
| 1+1+200 | One-shot | Semi-stand development: Sandy King gives 1+1+200 to 1+1+400 with agitation once a minute or less; about 30 minutes at 70 F for 1+1+200. |
| 1+2+100 | One-shot | Stronger solution B: develops to the same contrast index in much less time; useful for zonal expansion. |
Shelf life
- Concentrate
- Solution A about 6 months when made with phenidone; solution B not stated (Formulary sheet)
- Working Solution
- One-shot: use once and discard
One-shot.
Development times
Often used for
Stand developmentLarge format photographyAlternative process printingRotary processing
Limitations & warnings
- Catechol is toxic - handle carefully
- Must mix from raw chemicals
- Stain affects scanning density
- Less published data than PMK
Descriptions combine manufacturer specifications with community experience. Subjective assessments reflect common sentiment among photographers and may not match your results.