Solution A

Water (Distilled) 750.0 cc
Metol 10 g
Sodium Bisulphite 20.0 g
Pyrogallol 100.0 g
EDTA (optional) 5.0 g
Water to make 1000.0 cc

Solution B

Water (Distilled) 1400.0 cc
Sodium Metaborate 600 g
Water to make 2000.0 cc

Mix solution A with water at room temperature. Weigh out the Sodium Bisulphite first & add a 'pinch' of this to the water before adding the Metol, which must be dissolved completely before continuing.

Do not breathe the dust from any of the chemicals, particularly the Pyrogallol.

Mix solution A with water at room temperature. The Sodium Metaborate might not dissolve completely, but will slowly dissolve over a day or so.

Clearly label all bottle. If kept out of strong light & well stoppered, the shelf life of these solutions can be 10 years or so. After a week or so, the colour of the stock solution A will turn a pale yellow. This is normal.

Use: Mix 1 part A: 2 parts B: 100 parts water.

When the working solution is mixed, it will change colour from grey-green to pale amber. The is normal & if the colour doesn't change, there is something wrong & the solution should not be used.

Use immediately. Do not discard after use. After fixing, preferably with a non-hardening fixer, immerse the film in the used developer for 2 minutes, agitating every 30 seconds, to develop the Pyro stain. Discard the developer after this. Wash & dry the film as normal, remembering that the emulsion might be more delicate because of the non-hardening fixer.

Useful for retaining definition in highlight (>Zone X) negative areas. The emulsion speed is reduced approx. 50% in lower parts of the scale (highlight areas). Therefore expose film at manufacturers recommended speed. Test & adjust before using on anything important. The developer produces a stain which increases the printing contrast. Do not attempt to evaluate negatives without printing. Dev. times should be approx. 10-15 mins @ 20ºC.

It is recommended that anyone interested in using PMK seriously should read The Book of Pyro by Gordon Hutchings. Alternatively, Arem Publishing produce a CM Pyro kit (see manufacturers Suppliers on links pages).