Still Crazy After All These Years: Revisiting PMK Pyro

[Alan9940]

Photographer's Formulary typically has it.

They have been completely out of stock for both pre-mixed liquid and dry for quite some time; I've been checking every so often.

 

[Alan9940]

Alternatively instead of making a stock B solution you can simply mix as you go. Suppose you need a liter of working developer solution. Dissolve 6g sodium metaborate into 990ml water, add the 10ml of part A. Done.

I didn't think of doing this...thanks for the suggestion. Not sure why I didn't think of it, since I do this regularly with the Part B of ABC Pyro.

 

[John Wiegerink]

I didn't think of doing this...thanks for the suggestion. Not sure why I didn't think of it, since I do this regularly with the Part B of ABC Pyro.

I'm with you Alan and will mix my "B" just before I make my working solution. Certainly not that hard to do!

 

[retina_restoration]

They have been completely out of stock for both pre-mixed liquid and dry for quite some time; I've been checking every so often.

I make it from scratch, using the raw chemicals from ArtCraft.

 

[John Wiegerink]

I make it from scratch, using the raw chemicals from ArtCraft.

Me too Paul, but I always mixed the "B" as concentrate before and will now mix "B" as needed just before development.

 

[Milpool]

Me too Paul, but I always mixed the "B" as concentrate before and will now mix "B" as needed just before development.

If you’re mixing from scratch you could also choose to make a more dilute B stock if you have any trouble with the more concentrated stock. Say for example you make the stock B half as concentrated. Then you just need to use more of it to make the working solution. As long as the final working PMK solution has a concentration of 6g of metaborate per liter it doesn’t matter how you get there.

 

[Alan9940]

I make it from scratch, using the raw chemicals from ArtCraft.

Yeah, I mix all the formulas I use from raw chemicals. But, I've pretty much always had an issue getting all the sodium metaborate into solution, since it's such a concentrated solution. At one point, I thought of just buying a bottle of Part B from Bostick, but somewhere along the way I moved on to other pyro formulas.

 

[Alan9940]

If you’re mixing from scratch you could also choose to make a more dilute B stock if you have any trouble with the more concentrated stock.

This is what I eventually wound up doing but, for whatever reason, I didn't find even the half-strength easy to mix. I'm definitely going to give your 6g per L a try and see how I get on with that.

 

[Stephen Benskin]

TXP 4x5 in PMK Pyro. It takes a full 10 minutes to go from -1/2 to +1/2 with CI 0.56 in the middle. It's hard not to be in the ballpark.

3 CI vs Time curves. PMK Pryo, PMK Pyro read with blue channel, Xtol.

 

[chuckroast]

TXP 4x5 in PMK Pyro. It takes a full 10 minutes to go from -1/2 to +1/2 with CI 0.56 in the middle. It's hard not to be in the ballpark.

View attachment 421063

3 CI vs Time curves. PMK Pryo, PMK Pyro read with blue channel, Xtol.

View attachment 421064

How was this done? Continuous agitation? Open tank? Closed tank, hand agitate?

I have some skepticism that you can get to 20min without severe oxidation and loss of developer activity, but I'm willing to get schooled here...

 

[Stephen Benskin]

How was this done? Continuous agitation? Open tank? Closed tank, hand agitate?

I have some skepticism that you can get to 20min without severe oxidation and loss of developer activity, but I'm willing to get schooled here...

The data comes from an unfinished project I worked on with a partner. I didn't do the processing, but here are the notes.

 

[chuckroast]

The data comes from a unfinished project I worked on with a partner. I didn't do the processing, but here are the notes.

View attachment 421066

This would suggest continuous rotary processing for up to 20 min. I have never done rotary, so have no idea why how this would work.

Thanks for the response.

 

[Lachlan Young]

It takes a full 10 minutes to go from -1/2 to +1/2 with CI 0.56 in the middle

So many 'magic bullet' developers seem to turn out to largely involve massively widening the margin for gross operator error around a standard aim contrast.

 

[Raghu Kuvempunagar]

This would suggest continuous rotary processing for up to 20 min. I have never done rotary, so have no idea why how this would work.

This could be due to continuous agitation and the developer might have gotten oxidised severely after the initial 10 minutes. I checked the data for normal intermittent agitation here, and it tells a very different story.

 

[chuckroast]

This could be due to continuous agitation and the developer might have gotten oxidised severely after the initial 10 minutes. I checked the data for normal intermittent agitation here, and it tells a very different story.

This intuitively sounds correct

 

[Stephen Benskin]

So many 'magic bullet' developers seem to turn out to largely involve massively widening the margin for gross operator error around a standard aim contrast.

+1

 

[DREW WILEY]

Films differ. What you can get away with concerning Tri-X might prove very problematic with TMax films or Delta 100 (perhaps "disastrous" would be a more realistic term).

Another consideration is the drum rotation speed. I would select the lowest possible RPM; and even that would be too fast for me in terms of Jobo RPM's - way too much agitation.