View Full Version : PMK solution B saturation

Sylvester Graham
22-Mar-2007, 17:05
I've been using PMK for a number of years now.
I'm now noticing (and finally becoming concerned with) the percipitation in the mixed Solution B. Which is potassium...something? I can't remember what.

Anyhow, I understand the B solution is heavily saturated. I can never get the solution to mix completely. There's always a considerable amount (as in a film) across the bottom after a couple minutes of mixing. I notice it's been getting worse lately in my case. I do use distilled water. Is this a problem?


Claude Sapp
22-Mar-2007, 17:10
I have always been able to mix mine from powder thoroughly, my problem has been crystals settling out after sitting on the shelf for a bit. I have heated the B bottle and the crystals go back into solution, but even if I feel too lazy and dont mix the crystals back in, I have never noticed a problem in the developed negatives. I feel as long as Solution A is consistant, some crystals in the bottom of my Solution B bottle are not a problem.

Eric Woodbury
22-Mar-2007, 17:55
I've been using PMK for 17 years now. I had problems getting B to dissolve right from the beginning. Just too much powder into too little water. Every since I double the water and double the amount of B I use in the developer. I asked Gordon Hutchings one time why it was so concentrated. He said he wanted to keep the amount of B that is added to the final solution to a minimum so that the temperature of B didn't affect the final solution temperature significantly.

Even at the higher dilution, I get little crystal palaces forming in the winter time when it is colder in my darkroom. Sometimes I just add a little more B, sometimes not, and sometimes I make B from scratch. The results don't seem to vary as far as I can tell.

Keith Pitman
22-Mar-2007, 20:13
I had no problem with solution B for a long time, but have recently. I thought it might relate to a change in the chemical from the supplier (Photographers' Formulary). I ordered a new batch, but had the same experience. I've been diluting the B solution more to get it to disolve, and then using a higher proportion of solution A. I seem to be getting comparable results.

Chris Strobel
22-Mar-2007, 21:40
I just use the pre-mixed liquid solutions from Photographers' Formulary.No problems here.

23-Mar-2007, 05:44
Which is potassium...something? I can't remember what.

used to be called Kodalk now it is sodium metaborate