Instant Mytol Recipe

[BHuij]

Yeah, I would also be fascinated to see the differences between all three. There's every chance they're negligible or even invisible. But adding TEA just felt like one more variable that I didn't need to compromise on when I could just use a bit more glycol.

 

[measwel]

@sufnturf

The concentration of AA does not have to be so high for FX-55 as to warrant using TEA.
I advice against using it. I experimented with it and the resulting negatives were inferior to those developed with FX-55 without TEA.
TEA is a base and a "amino alcohol" and has an effect on grain and contrast even in low concentrations.

The following formulation works perfectly well and comes very close to the original FX-55 formula.
The only difference is, that potassium ascorbate is the developing agent, instead of sodium ascorbate.
That does not matter though, as both are chemically equivalent if you factor in their molecular weight - which this formula does.

******************** PC Stock ********************

100 ml glycol at 50 C
12 g ascorbic acid (*1)
1 g Phenidone

******************** F Stock ********************

Warm water (70 C) : 700 ml - fill to 1 Litre after dissolving chemicals
Potassium carbonate anhydrous: 25 g to 28 g (*2)
Sodium bicarbonate : 1.5 g
Sodium sulfite anhydrous : 25 g
Sodium metabisulphite : 10 g

******************** FX-55 FILM DEVELOPER - FROM PC F Stock ********************

5 ml PC F Stock (0.05 g P, 0.6 g AA)
50 ml F Stock
Warm water (70 C) : top up to 500 ml (*3)

(*1) Takes a good while to dissolve, but it does so eventually. Do not heat above 70 degrees centigrade.

(*2) The original formula calls for 20 g of p. carbonate. When using ascorbic acid, some of the p. carbonate will react with it to form potassium ascorbate (our developing agent). The stoichiometric amount is 5 g of p. carbonate for 12 g or ascorbic acid. So we need a starting amount of 25g. However, in my case 27.5 g of p. carbonate works better. With 25g I found the activity and end contrast to be too low. This could be due to my p. carbonate not being lab grade 100% pure. Or because I like more contrast than the standard formula delivers.

(*3) Obviously use double the amount of stock solution if you make 1 litre of developer.

So if you go this route, start with 25g and test if the developer is active enough.
If it is not, then add a gram of potassium carbonate to the stock solution until you get the development time and contrast to your liking.
It should be in the range of 25 to 28 grams.

Shelf time is almost indefinite for both solutions.
Results are most likely identical to FX-55.

 

[john_s]

@sufnturf

The concentration of AA does not have to be so high for FX-55 as to warrant using TEA.
I advice against using it. I experimented with it and the resulting negatives were inferior to those developed with FX-55 without TEA.
TEA is a base and a "amino alcohol" and has an effect on grain and contrast even in low concentrations.

Gainer originally recommended a little TEA to aid in pH adjustment if using ascorbic acid instead of sodium ascorbate. John Finch increased the amount of it quite a lot, enough, possibly, to raise the pH and accordingly increase film speed and change other characteristics. Hence, perhaps, his claim of a significant speed increase.

I use Microphen when I need a bit more speed, but was wondering if FX-55 might be better (less grainy look?). It does have a lot more phenidone than PC-512.