Adox in PMK Pyro results.

Test stips at twenty and ten
Minutes

The results are in! This has turned out to be one of the most exasperating tests to date. There have been problems all along the way from getting the exposures right to developing the film. Having said that there have been some surprises.

As with the Agfa test the film was exposed at box speed ISO 100 in the Nikon F5. This is where the process changes apart from the test method. The PMK Pyro used was one I made from raw material that did not include EDTA disodium in the mix and a reduced amount of Sodium Metaborate in solution B.

Sequence of development:

●         Pre-soak - it makes no difference with this film. It is not prone to air bell/bubbles sticking to the film.

●         Developer - to be made up immediately before use at 21 degrees C.

●         Development times - for this test were 5, 10, and 20 minutes respectively.

●         Tank inversions - continuously for the first minute and then once every fifteen seconds.

●         Stop, Fix and wash - as normal.

●         After bath - was not used and would have made little difference with this mix.

Notes:

Adox CHS 100 PET 35mm is not like other black and white film it has a noticeable thinner film base which is coloured blue. The cassette this film came in was not light tight which almost ruined the test. I only discovered this after the film had been exposed, when removing the film from the cassette it fell to bits. I have read a forum thread saying that the 120 roll film has the same problem. Adox you need to up your game! It is appalling quality control.

Pre-soak water after use

If you use a pre-soak the water will come out blue.

The ten minute development time is the one suggested by Digital truth, which made it the reference time the other test strips were to be judged against.

Results

All the test strips including the one thats a no show.

The test strip to show the best density of negative is the twenty minute one, having said that they are still a bit on the thin side. This does not take away from the fact that they are fully toned and well defined. There is no sign of grain when enlarged to 485 mm (19”) by 340 mm (13.5”). When printing the negatives I'm having to use grade three, normally I would expect to be using grade two, this could be due to the lack of EDTA in the mix of Pyro used. I'm also disappointed that the five minute test strip shows no negatives at all, from previous experience the shorter/half development times have a faint out line. In this case I can only put it down to the faulty film cassette. The ten minute test strip is very thin when compared to the Agfa test strips it is thinner than the half development time. Which suggests that normal development in this case should be greater than twenty minutes.

Over sized enlargment

With all the time and effort put into this test the last thing I was expecting was to be let down by bad manufacture. Of the thirty six exposures on the film around about  ten frames are unaffected by some light damage luckily the majority of these are from the test exposures that put in an appearance. If there was going to be any question marks I was thinking it would be from the developer but it did not disappoint, the only thing to note was when i poured it from the developing tank it was a lovely pink rose colour.

Will I be using the film again? Yes! only because I have a roll of 120 on the shelf if the negatives show any light damage then I will not use it again. How can I say that when I use a lot of out of date film? With out of date film at least you know that the results could be iffy. You don't expect it from new in date stock.

Used PMK Pyro.

Making up PMK Pyro from Raw.

This is the first time I've mixed a developer from scratch. I find when  preparing for something that is new, it seems to take an inordinately long time to set up. This has been no different and I can understand why more people do not mix for themselves.

Before you start.

If you have just purchased new scales it is a good idea to check how accurate they are. First thing to do is place the scales where you plan to make up the mix and zero them.The table that follows is a simple and affective way of checking the accuracy.

These weights came from the royal mint:

Coin test

        ●         1p – 3.56 grams.

●         2p – 7.12 grams.

●         5p – 3.25 grams.

●         10p – 6.5 grams.

●         20p – 3.0 grams.

●         50p – 8.0 grams.

●         £1 – 9.5 grams.

●         £2 – 12 grams.

An alternative to using scales is the Twenty P mix. This is where twenty p coins are used as a counter balance to weighing out the powders. While talking about alternative ways of measuring out you can use measuring spoons. This could be a more reliable way of ensuring that each mix is consistent. If you measure out the chemicals with number of spoons it will not matter that the powders have changed in volume by absorbing moisture or drying out.

With the checks out of the way what next? How much are you going to make up as stock solution? I know from previous use that it will keep for a very long time, even years. I personally prefer only to have small amounts of developer on the shelf ready for use. This is partly because I use several different film and paper developers.  Anchells Darkroom Cookbook  suggests that you make up part A at 750 mls and part B at 1400 mls; well that is a large amount for a first mix not only that what happens if you get it wrong  or heaven forbid it does not work. Luckily Trevor Crone has published the weights for a smaller amount:

Solution A to make 250mls:

●         Metol 2.5 grams

●         Sodium metabisulphite 5.0 grams.

●         Pyrogallol 25.0 grams.

Solution B to make 500mls

●         Sodium Metaborate 125 grams.

Stock solution should be made up with distilled/de ionised water. EDTA-disodium is an optional ingredient It adds gold tone to the silver of the film.

Trevor suggests a reduction of 10 grams for solution B to help combat separation when mixed. He has also said that to his knowledge it has not affected the quality of his negatives.  I can confirm the drop out is reduced but I think this is mainly due to the reduction of powder. Although these quantities are more reasonable  I made my batch up at half these weights.

Other bits

Paper cup cake holders are a good idea for pouring the powders into when it comes to measuring out but they will only cope safely with small weights. You can get plastic cups to do the job which maybe a better route to take if you plan to mix all your own chemicals.

Common sense should prevail when it comes to measuring out these powders. Gloves and a breathing mask should be the minimum safety precautions taken. If the powder gets air born it will irritate the lining of your nose. Also if you get it on your hands it  will irritate or burn your skin. So please be sensible.  

Adox CHS 100 Pet ISO 100 35mm flim.
Developed in PMK Pyro,
Printed on silverproof paper,
Developed in Ilford warm tone.

Having purchased all the ingredients to mix it myself, is it more cost affective? The over the counter premixed price of PMK is about £9 for 10 litres. The cost of all the ingredients is around £39. The batch that I made up  was equivalent to ten litres and saved about 50p. Taking every thing into account scales, time, safety etc. etc., it may not be worth all the trouble and money as a one off. There are advantages to this method such as the flexibility of making up the quantities of developer, stop and fix you require and being able to try out other developers you would not normal be able to get from the mainstream. The main purpose for me was to ensure a ready supply of PMK Pyro. Now that I have started down this road as my stop,fix and other developers run out they will probably be replaced with powdered formulas.

Acknowledgements and Thanks to the following:

Paul C, for the royal mint weights. 

Mr S. Nichols for the 20 P mix.

Trevor Crone for the reduced PMK Pyro mix.