PMK solution B

[kev curry]

Ive just developed a roll of 120 in PMK and the negs are strangely under developed. Nothing in my procedure has changed, but Ive noticed that solution B is very cloudy (precipitation?) Could this be the cause of the underdevelopment?

[Drew Wiley]

Yes. Was the storage environment cold? You could try gently shaking it, or filtering it back and forth several times (until everything is dissolved and nothing discarded).

[percepts]

If its in a bottle which it should be, then just run the bottle under a hot tap for a few seconds to warm it and then shake it a bit. Repeat until all that milkiness disappears.
Do not filter it. You will just make things worse if you do that.

[Eric Woodbury]

My "B" eventually grew crystals, so I mix "B" fresh every time. 6gr/liter

[kev curry]

Yes the storage environment is pretty cold, the Scottish winters just arriving:) I've warmed the bottle on the radiator and its went back into solution, problem solved. I'll keep an eye out for those crystals! Thanks folks.

[Drew Wiley]

I should indeed have clarified that if you filter it, use a screen funnel, where all the
precipitate will become dissoved as you pour the solution back through several times.
Filter paper would certainly be inappropriate, or anything else where the volume
concentrate becomes altered.

[Eric Woodbury]

Has anybody tried using TEA for solution B instead of the standard? Is the pH close enough?

[kev curry]

Eric, when you say 'TEA' do you mean tea as in 'Tetley' tea or is 'TEA' a chemical?
No shit, serious question:)

[percepts]

Eric, when you say 'TEA' do you mean tea as in 'Tetley' tea or is 'TEA' a chemical?
No shit, serious question:)

Triethanolamine, used in various devlopers I think as a PH balancer but don't quote me on that.

[Eric Woodbury]

TEA = triethanolamine. TEA is a very interesting chemical.

I'm not a chemist, but I think TEA pH is close to 10 at 1%, while Kodalk is a little higher.

[kev curry]

Ive been developing film today and the negs are looking beautiful, what a difference heating solution B has made to contrast! PMK negs rock! Time for tea:)
Thanks again.

[kev curry]

My "B" eventually grew crystals, so I mix "B" fresh every time. 6gr/liter

That'll be 6g to a litre of PMK working soluton right? Just checking;)

Trying to get those crystals back into solution is a pain. I'm finally taking your advice Eric.

[Doremus Scudder]

Eric,

Another solution (pun intended) is to simply mix your solution B in twice as much distilled water and then use twice as much when mixing your working solution (or, if you are a real stickler, you can subtract the extra volume from the water you start with). PMK solution B is a saturated solution and tends to cloud or precipitate when it gets cold or if you mix it with anything else but distilled water.

And, if you do have a scales handy, you can just measure out the dry chemical when mixing the working solution. Just be extra sure that it all dissolves completely before developing film.

Best,

Doremus