Modified E-72 and FX-55

[measwel]

Inspired by all the great two part phenidone-ascorbic-acid developers out there, I wondered if it would be possible to modify the formulas for the E-72 paper developer and the FX-55 film developer, so they could use the same universal part B, without compromising on the quality. If possible, one could keep just 3 bottles of stock and simplify the whole mixing procedure. As I learned from reading Mr. Gainer his posts, the amount of ascorbic acid in relation to the phenidone may be adjusted quite freely in part B, without impacting the development properties too much, as long as the ratio is at least 40 to 1 and part A sets the alkalinity of the working solution right. So I came up with the following idea for the universal part B solution:

**** UNIVERSAL PART B ****

H2O (70 C) : 40 ml
Triethanolamine (70 C) : 40 ml
Ascorbic Acid (Vitamin C) : 50 g
Propylene Glycol (70 C) : top up to 100 ml in total
Phenidone : 1 g
Potassium Bromide* : 1 g (Optional. see E-72 part A formula)

* Should slightly increase contrast and prevent blown out highlights.

10 ml of this would provide:

Phenidone : 0.1 g
Ascorbic Acid : 5 g
Potassium Bromide : 0.1 g
TEA : 4 ml

P to C ratio = 1:50.

Alternatively, I might try topping it up to 200 ml with the glycol, in case I have trouble dissolving the other chemicals in a 100 ml of total volume.

 

[measwel]

For the modified E-72 developer, I came up with the following idea:

**** MODIFIED E-72 PAPER DEVELOPER - PART A ****

Warm water (70 C) : 700 ml - fill to 1 Litre after dissolving chemicals
Sodium carbonate anhydrous* : 231 g
Sodium sulfite (anhydrous) : 135 g
Potassium bromide : 4.7 g if you use bromide in part B OR 5.7 g is you don't.

* Do not simply use washing soda as a substitute.
Washing soda could be the decahydrate or the monohydrate or the anhydrous form (a.k.a. pure soda).
If you only have decahydrate or monohydrate around, heat it at 110 C for one hour to get the anhydrous form.
If it loses weight, it was either the decahydrate or monohydrate. Store airtight.

To make 1000 ml of developer: 100 ml part A + 10 ml universal part B + water to 1 litre

The differences with the original E-72 formulation are:

All ingredients are trippled in concentration, so less of the stock solution is need.
Slightly less bromide is added as some of it comes from the universal part B stock solution.

100 ml of this plus 10 ml of part B would provide:

Sodium carbonate : 23.1 g
Sodium sulfite : 13.5 g
Potassium bromide : 0.57 g (0.1 g comes from part B)
Phenidone : 0.1 g
Ascorbic Acid : 5 g
TEA : 4 ml

P to C ratio = 1:50

In the original E-72 1:3 working solution, that is:

Sodium carbonate : 19.25 g
Sodium sulfite : 11.25 g
Potassium Bromide : 0.475 g
Phenidone : 0.075 g
Ascorbic Acid : 4.75 g
TEA : 0 ml

P to C ratio = 1:63.33

I believe the modified E-72 part A with the universal part B, should work almost the same as the original E-72 1:3 working solution.
The P to C ratio would be slightly lower, but still sufficient and the higher concentration of C offset by the 4 ml of TEA.

I have not tried it yet, so this is just theory for now.
If anyone has any thoughts on this, or suggestion on how to tweak the formulation, I would be very happy to hear them.

 

[measwel]

For the modified FX-55 developer, I came up with the following idea:

**** MODIFIED FX-55 FILM DEVELOPER - PART A ****

Warm water (70 C) : 700 ml - fill to 1 Litre after dissolving chemicals
Potassium carbonate* : 42 g
Sodium sulfite (anhydrous) : 25 g
Sodium metabisulphite : 10 g

* About 22 grams of potassium carbonate are needed to convert 50 grams of ascorbic acid into potassium ascorbate.
** Not sure if any will be left as it also react with ascorbic acid.

To make 1000 ml of developer: 100 ml part A + 10 ml universal part B + water to 1 litre

The differences with the original FX-55 formulation are:

More potassium carbonate, as about half of it will react with the ascorbic acid and form potassium ascorbate.
The developing agent would be potassium ascorbate instead of sodium ascorbate and the concentration would be higher.
Presence of TEA and Potassium Bromide in the working solution.
Slightly less sodium metabisulphite to help with contrast and speed.
No sodium bicarbonate as some of it would form sodium ascorbate and whatever is left from the 0.15 g that is in the original formula, won't be that relevant anyhow.

100 ml of this plus 10 ml of part B would provide:

Potassium carbonate : 4.2 g -> 2 g (About 2.2 g of the 4.2 g would get converted to potassium ascorbate)
Sodium sulfite (anhydrous) : 2.5 g
Sodium metabisulphite : 1 g
Potassium ascorbate : 6.1 g
Phenidone : 0.1 g
Potassium Bromide : 0.1 g
TEA : 4 ml

P to C (potassium ascorbate) ratio = 1:61

In the original FX-55 1:9 working solution, that is:

Potassium carbonate : 2 g
Sodium sulfite (anhydrous) : 2.5 g
Sodium metabisulphite : 1.2 g
Sodium Ascorbate : 1.3 g
Phenidone : 0.1 g
Sodium bicarbonate (backing soda) : 0.15 g

P to C (sodium ascorbate) ratio = 1:13

Here is where it gets interesting.
When the ascorbic acid gets converted to potassium ascorbate, the modified formula will have a much higher potassium ascorbate to phenidone ratio than the original sodium ascorbate to phenidone ratio (61:1 vs 13:1).
This should not be a problem though, as a ratio of 40 to 1 or higher is fine.
Both potassium ascorbate and sodium ascorbate have similar development properties and PH.
There will be no 0.15 g of sodium bicarbonate in the solution, but I believe this should not matter.

The alkalinity will probably be slightly higher, as the TEA is alkali.
A high concentration of potassium ascorbate and higher alkalinity will probably result in increased activity.
This should presumably be tempered by the Bromide, which is not present in the original formula.

Uncertainties:
I am unsure, if it makes sense to adjust the concentration of the potassium carbonate, to adjust the alkalinity and the density of the negative.
I am usure about the potassium bromide. Bromide is not present in FX-55. But it is in PC-TEA. So I keep it for now, assuming it might help temper down the activity from the extra potassium ascorbate and higher alkalinity.

To make this work just right, I guess one has to find the optimal concentration for the potassium carbonate and possibly think about the bromide and sodium bicarbonate concentration in part B.

 

[measwel]

The beauty is, if the above can be made to work, then one could mix one of the best paper developers and one of the best film developers in exactly the same way.

100 ml of part A + 10 ml of part B + water to 1 litre.

One would need to prepare only one part B solution.
Everything could be kept in 3 bottles.
It would be cheap, simple, eco-friendly and last for years.

 

[John Wiegerink]

I don't use either, but I'm always looking for easier, simpler ways to do everything. At my advanced age that's very important time wise and body wise. My wife keeps telling me to work smarter, not harder. I think the only way you are going to solve your curiosity is to mix a batch of both and give it a whirl. If you have experience with both developers you'll know soon enough if your experiment was successful or not. Good luck!

 

[BHuij]

Interesting concept. How does FX-55 compare to Mytol? Every time I try something besides Mytol in 35mm, I end up just wishing it had the ultra-fine grain of Mytol... haha. Very happy with E-72 for paper though, for the past few years.

 

[Alan Johnson]

OP, you are aware that the pH of a typical paper developer is around 10.5 and the pH of FX-55 about 8.3?

Crawley's low pH developer

FX 55 got initial publicity as a way of preserving ascorbate, but noticing it seemed to have a low pH I measured the pH of the working solution from post 4 below as 8.3 +/- 0.1 which is about the lowest for an acutance developer so I decided to test it for granularity...

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