What if FX-55 and PC-Glycol had a baby?

[darkroommike]

FX-55 has (for want of a better term) a concentrated activator stock solution mixed with dry developer agents: sodium ascorbate-L and phenidone. The activator is a buffered concentrate and diluted 1+9 to make a working solution to which a ridiculously small amount of dry phenidone is added (approximately enough to cover the head of a pin--I jest).

PC-Glycol is a percentage solution of phenidone and Vitamin C that you dilute in a freshly made activator solution.

See where this is going?

So far this is just a thought experiment for me...

 

[koraks]

That should work.

 

[Alan Johnson]

Pat Gainer was the first to provide such a formula, here is mine from soon after:

FX-55 tonality

FX-55 is Geoffrey Crawley's new ascorbate developer. I mention it because it appears to give a rather special tonality. Mine was made up in propylene glycol using excess potassium carbonate,as suggested by Patrick Gainer: www.apug.org/forums/forum37/53995-new-fx-55-developer.html If...

www.photrio.com

Now I think that my conclusion
"No perceptible difference in grain or acutance on 8x enlargement."
was due to the prints not being large enough. FX-55 has a pH about 8 compared to about 9 for PC-TEA.

 

[Andrew O'Neill]

I'd like to hear more of your thought experiments...

 

[darkroommike]

Pat Gainer was the first to provide such a formula, here is mine from soon after:

FX-55 tonality

FX-55 is Geoffrey Crawley's new ascorbate developer. I mention it because it appears to give a rather special tonality. Mine was made up in propylene glycol using excess potassium carbonate,as suggested by Patrick Gainer: www.apug.org/forums/forum37/53995-new-fx-55-developer.html If...

www.photrio.com

Now I think that my conclusion
"No perceptible difference in grain or acutance on 8x enlargement."
was due to the prints not being large enough. FX-55 has a pH about 8 compared to about 9 for PC-TEA.

I found your post after I made my post this morning.

Crawley FX-55 uses ascorbate not ascorbic acid, I suspect that makes a big difference. Gainer used TEA in his Part B, which is quite alkaline and neutralizes the ascorbic acid. Again, I'm just thinking (and it hurts), my last chemistry class was 50 years ago.

 

[Alan Johnson]

I have not done the calculation again but my formula would have increased the potassium carbonate to balance the ascorbic acid and give the same pH as FX-55, essentially the same working solution except for the glycol. It should make no detectable difference. They are partly ionized at this pH and float around as ions that participate in the development ,not as the ascorbate-metal compound.
The concentration of ions involved in the development depends only on the pH, the film does not know where they came from, carbonate or ethanolamine.

 

[Alan9940]

I've mixed a 1% solution of phenidone in propylene glycol for years to be used in various formulas calling for very small amounts of this chemical. No problem using it in the FX-55 formula, in my experience.

 

[pentaxuser]

I found your post after I made my post this morning.

Crawley FX-55 uses ascorbate not ascorbic acid, I suspect that makes a big difference. Gainer used TEA in his Part B, which is quite alkaline and neutralizes the ascorbic acid. Again, I'm just thinking (and it hurts), my last chemistry class was 50 years ago.

Anyone interested in this might want to have a look at forthcoming videos by John Finch on FX55. He has already done several including ones involving its actual use. In the forthcoming set of videos he has said he will be using ascorbic acid and presumably explaining what needs to be changed when using ascorbic acid

It looks as if it might be worth a look

pentaxuser

 

[koraks]

Crawley FX-55 uses ascorbate not ascorbic acid, I suspect that makes a big difference

Nah.
It's basically the same stuff give or take a proton.

Gainer used TEA in his Part B, which is quite alkaline and neutralizes the ascorbic acid.

...into...indeed, ascorbate.

 

[Sidd]

Here is the John Finch's video on making a PG solution of FX-55 part B.