Review: Bergger PMK film developer – David Tatnall

Pyrogallol (Pyro) was one of the first developing agents created and was popular in the 19^th century. However, despite the outstanding negative quality that traditional pyro produced, it was regarded as problematic to use and lost favour as a standard developer when easier to use developing agents were discovered. It regained popularity with fine art and alternative photography practitioners in the 20^th century when photographers such as Edward Weston began using it.

I first became aware of pyro developer in the 1970’s through Melbourne photographer Ian Lobb. Ian’s prints have a luminosity and strength that showcase pyro’s tonality. I used the ABC Pyro formulation mixed up from powder chemicals for a long period of time until the availability of the chemicals became problematic.

There are several different variations of pyro developers including: ABC Pyro, Pyro 510, Pyrocat-HD and PMK that are available today.

This review is about Bergger PMK. PMK stands for Pyro – Metol – Kodalk (Kodalk is a Kodak trade name for sodium metaborate).

This version of the developer was formulated by Gordon Hutchings to create a more universal developer adapted to a wide range of modern films and light conditions.

PMK is a tan staining developer. The stain masks silver grain and gives a less grainy smoother look to negatives. When a stained negative is printed on variable contrast silver papers the yellowish/brown stain acts like a low-contrast variable contrast filter resulting in a more tonal image. This staining and tanning can provide a definite increase in both the printing quality of the negative and its capacity to record subtle tonality and highlight separation. It also masks inherent grain and increases acutance.

Bergger PMK is a two-part liquid developer: part A is 250ml, part B is 500ml. This concentrate will make 25 litres of working solution. The shelf life of the stock solution is exceptionally long. Working solution is mixed 1+ 2+ 100 and should be used straight away. Leaving the working solution too long may cause oxidation resulting in negatives tanned more brown than required.

To make a working solution of PMK start with a 1000ml of water at 21ºc add 10ml of part A, then add 20ml of part B, at this stage the liquid will change from a grey/green to pale amber. You now have 1030ml of working solution. With this you can process either: two sheets of 8×10, eight sheets of 4×5, two rolls of 120 or two rolls of 135.36.

There are a few modifications in processing with PMK: pre wetting of the film for 3 to 5 minutes is recommended to ensure even development and the use if a non-acidic stop bath will help preserve the negative stain.

PMK developer decreases film speed (a list of film types and suggested ISO settings and development times can be seen on Bergger’s data sheet).

I have had great success using FP4+ rated at 80 ISO and developed for 10 minutes at 21ºc. I process sheet film in trays. Bergger PMK can also be used in either deep tanks or daylight tanks.

The quality of the negatives produced with Bergger PMK have increased sharpness, very fine grain and low fog, making the printing of high-quality prints with subtle tonality on fibre-based variable contrast paper a joy.

Compared to the older variations of pyro developers Bergger PMK is a very easy developer to use, shelf life of the stock solution is outstanding. With it it’s possible to process roll film or sheet film easily with predicable and repeatable results. Negatives can be scanned by drum or flatbed scanners easily with very good results.

In Australia Bergger PMK and other Bergger products are available at Gold Street Studios.

Below are some recent silver gelatin prints made from FP4+ 4×5 negatives that have been processed in Bergger PMK.