Modified E-72 and FX-55

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.

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.

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* : 40 g
Sodium bicarbonate** : 1.5 g
Sodium sulfite (anhydrous) : 25 g
Sodium metabisulphite : 10 g

* About 20 grams of potassium carbonate are needed to convert 50 grams of ascorbic acid into potassium ascorbate.
** Not sure if how much will be left as a bit of it will 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 g -> 2 g (About 2 g of the 4 g would get converted to potassium ascorbate)
Sodium bicarbonate : 1.4 g or thereabout
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 bicarbonate : 1.5 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.

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.

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!

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.

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?

BHuij said:

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.

Click to expand...

It is supposed to be a medium size grain developer with very high sharpness and acutance.

Watch minute 18:30.

Minute 10.

Grain can be reduced by more dillation. Minute 9.

Also see: https://www.photrio.com/forum/threads/crawleys-low-ph-developer.154080/

BHuij said:

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.

Click to expand...

PS the formula I am working on, will, unlike the original formula, contain Triethanolamine, which is a solvent, making the developer a solvent one.
This will presumably lead to a finer grain than that produced by the original FX-55.

Only one way to find out really

Alan Johnson said:

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...

www.photrio.com

Click to expand...

Yeah, the alkalinity of the formula I am working on will probably be higher than 8.3 due to the TEA. Maybe it will have to be balanced by adding more sodium metabisulphate, maybe not. I guess in my experimentation I will have to consider the influence of the concentrations of:

potassium carbonate : +PH / activity
sodium metabisulphite : -PH / contrast / activity
potassium bromide : fogging / highlights
sodium bicarbonate: PH / fogging / highlights

This is what I have in mind:

Goal; test the influence of the concentration of:

• potassium carbonate : +PH / activity
• sodium metabisulphite : -PH / contrast / activity
• potassium bromide : fogging / highlights
• sodium bicarbonate - fogging / highlights

Assumption 1; full development to pitch black at 20 C in about 5 minutes would be good. That means both sides of a film teststrip show full black. Would correspond with my times for HC-110 stock B solution.
Assumption 2; 0.1 g of bromide and / or 0.15 g of sodium bicarbonate in 1 litre of developer can have contrast enhancing and anti-fogging properties, but a negligible influence on development time and PH.
Assumption 3; About 2 g of potassium carbonate will react with the AA and form potassium ascorbate.
Assumption 4; The experiment can take place in 2 phases. In phase 1, the potassium carbonate and sodium metasulphite are adjusted to get the activity and PH right. Secondly, the influence of the bromide and bicarbonate can be tested as they will have virtually no impact on PH and mainly influence the highlights / contrast / grain.

Film; fomapan 100@100, the same scene on a 36 roll cut into pieces.

I will start with a batch without potassium bromide and sodium bicarbonate in it.
Then use test strips to find a formula that makes the strip go fully black in about 6 minutes and adjust PH to about 8.5 to match the original formula.
Then I will do some same-frame development with this solution, adjusting the bromide and bicarbonate.

measwel said:

PS the formula I am working on, will, unlike the original formula, contain Triethanolamine, which is a solvent, making the developer a solvent one.
This will presumably lead to a finer grain than that produced by the original FX-55.

Only one way to find out really

Click to expand...

If so, higher dilution will make it more of an acutance developer thereby sharpening the grain and making it more pronounced, all other things being equal.

I think the trick will be to get the potassium bromide and sodium bicarbonate concentrations right.

Let's see what AI has to say about their impact.

On grain:

Potassium bromide
Decreases grain in film developer by acting as a restrainer, which slows down the developing process overall and prevents unexposed crystals from developing, thereby reducing fog. This slowing effect helps to achieve finer grain and better contrast, though it also increases the total development time needed.

Sodium bicarbonate
Adding sodium bicarbonate makes the developer more alkaline. Higher alkalinity can speed up development, but it can also lead to a more aggressive reaction, resulting in a larger, more textured grain.

Note; in case of FX-55 the alkalinity should not change. It will act as a PH buffer if it does anything at all.

Triethanolamine
Triethanolamine does not directly increase or decrease grain, but it can influence the developer's characteristics to indirectly affect grain, primarily by acting as a stabilizer and pH buffer. It is often used to extend the life of a developer by preventing the active ingredients from degrading and can help produce a smoother, more even development process, which typically results in finer grain.

On contrast:

Potassium bromide
Potassium bromide decreases contrast in film developer by acting as a restrainer, which slows the development process and prevents the developer from acting on unexposed silver halides. This effect "restrains" the development of the areas that were exposed to light, reducing fog and moderating the overall development rate. By reducing the speed of the developer, it specifically slows down the development of highlights while allowing shadows to develop more fully, which can have a moderating effect on the final contrast.

Sodium bicarbonate
When used as the primary alkali to raise the pH, it increases contrast because a higher pH speeds up development and can lead to a greater difference between light and dark areas. However, when used as a buffering agent to lower contrast, as in low-contrast developers like TDLC-103, it serves to buffer the pH and can create more mid-tones.

Come to think of it, maybe I should not experiment with Sodium bicarbonate at all and just leave it out. The TEA is a PH buffer.
I have no idea why it sodium bicarbonate is in the original FX-55 formulation and my feeling tells me it can be left out in the presence of TEA.

30 minutes later; yeah, I will leave it out. I see no point in having 0.15 g of it in 1 L with a part reacting away with the AA. Contrast can be controlled by bromium and the metasulphite too.

BHuij said:

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.

Click to expand...

In my experience, Mytol and FX-55 are nearly identical in behavior/results.

retina_restoration said:

In my experience, Mytol and FX-55 are nearly identical in behavior/results.

Click to expand...

That's great to know. I have high hopes for my modified FX-55 experiment.

measwel said:

That's great to know. I have high hopes for my modified FX-55 experiment.

Click to expand...

I have migrated to using the "stock solution" version of FX-55 and Phenidone in Glycol rather than Mytol, since Mytol has a very short shelf life compared to FX-55. Both developers deliver nearly identical results, but I favor FX-55 for its convenience.

My game plan is:

PREPARATION

Part Z1
Dissolve 5 g potassium carbonate in 50 ml of water
1 ml will hold 0.1 g of potassium carbonate

Part Z2
Dissolve 1 g sodium metabisulphite in 10 ml of water
1 ml will hold 0.1 g of sodium metabisulphite

Part Z3
Dissolve 1 g potassium bromide in 50 ml of water
1 ml will hold 0.02 g of potassium bromide

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 : LEAVE OUT

Part A
Potassium carbonate : 2 g (all will be converted to potassium ascorbate)
Sodium bicarbonate : LEAVE OUT
Sodium sulfite (anhydrous) : 2.5 g
Sodium metabisulphite : 1 g
fill to 1000 ml

Take A + 10 ml of B resulting in:

Working solution W
Potassium carbonate : 0 g (should be 2 g to match the original formula)
Sodium bicarbonate : 0 g
Potassium Bromide : 0 g
Sodium sulfite (anhydrous) : 2.5 g
Sodium metabisulphite : 1 g
Triethanolamine : 4 ml
Potassium Ascorbate : 5.6 g
Phenidone : 0.1 g

Test PH. AI predicts it will be around 5 or 6 with 4 ml TEA and 1 g of metabisulphate. But what does AI know right?

Add potassium carbonate (1 ml Z1) in 0.1 gram increments. Keep testing PH. Note how much potassium carbonate went in there.
Keep adding until development time of a test strip is around 5 minutes or PH around 8.5. Whatever comes first.
If more potassium carbonate is needed to get decent activity, consider adding more sodium metabisulphate (Z2) to balance the PH back to 8.5.
Just don't overdo it, as the metabisulphate will allegedly decrease contrast. Maybe it is better to content with a higher PH than in the original formulation.

Once a working solution W is found with decent activity, develop the same frame for different concentrations of bromide.

DEV1 : 0 g bromide
DEV2 : 0.02 g bromide (add 1 ml Z3)
DEV3 : 0.04 g bromide (add another 1 ml Z3)
DEV4 : 0.06 g bromide and so ...
DEV5 : 0.08 g bromide
DEV6 : 0.1 g bromide

That should do it to find an optimum.

1 litre of PC-TEA working solution holds 0.04 g of bromide, so that could be a reference point.

I guess I will use the same patterson tank, so I will be playing around developing for at least an hour.
Then making sure I note which frame had what bromide concentration.
Then scan and compare.

I would love it, if somebody else would care to repeat this experiment, so I get some confirmation about the results.

I'll be very curious to see what you come up with. Not sure I have the time to dedicate to developer experimentation right now, but I will follow with interest

BHuij said:

I'll be very curious to see what you come up with. Not sure I have the time to dedicate to developer experimentation right now, but I will follow with interest

Click to expand...

I will try to come up with a formula which produces fine grain, so it will be usable for 35mm too. That should be possible if I can get the balance right of the active ingredients:

• Potassium carbonate - Speeds up development, increases grain, increases acutance. Strongly alkaline. PH 11. PH buffer in the 10 to 11 range.
• Sodium sulfite - Limited influence on development speed, anti oxidant, reduces grain, improves the overall tonality and sharpness, increases acutance. Slightly alkaline. PH 9. Not a buffer.
• Sodium metabisulphite - Slows development, anti oxidant, lowers grain, increases acutance. Strongly acidic. PH 4. PH buffer in the 2.5 to 5.5 range.
• Sodium bicarbonate (backing soda) - Speeds up development slightly. Lowers contrast. Can prevent highlights "blowing out". PH 8.3. Weak PH buffer in the 7.2 to 7.6 range.
• Triethanolamine - Solvent, reduces grain, PH 11 at 1%. PH buffer in the 7 to 8.3 range.
• Potassium Bromide - Slows development. Reduces grain. Anti fogging. Can prevent highlights "blowing out". PH 8.5.

To lower the variables, I will probably not bother with the bicarbonate. There is little of it in the original formula and I don't think it is needed as a buffer, since the new formula will have Triethanolamine, which buffers in the same PH range.

I rethought my thought experiment and I think I thought wrong. The TEA in the modified formula will rise the alkalinity of the working solution.
So my improved game plan is:

Z1
Dissolve 1 g sodium metabisulphite in 40 ml of water.

Z2
Dissolve 1 g potassium bromide in 100 ml of water

A
Potassium carbonate : 4g (2g will be left like in the original, the rest will convert to potassium ascorbate)
Sodium sulfite (anhydrous) : 2.5 g
Sodium metabisulphite : 1 g
Sodium bicarbonate: 0.15g
fill with water to 1 litre, split into A1 and A2

B1
Triethanolamine (70 C) : 38 ml
Water : 38 ml
Ascorbic Acid (Vitamin C) : 50 g
Phenidone : 1 g
Propylene Glycol (70 C) : top up to 100 ml in total

B2
Ascorbic Acid (Vitamin C) : 50 g
Phenidone : 1 g
Propylene Glycol (70 C) : top up to 150 ml in total

Experiment 1

A1 + 7.5 ml B2

PH should be around 8.3 like in the original, as the AA will convert into the neutral potassium ascorbate and the glycol is neutral too.

Develop a test strip.

Experiment 2

A2 + 5 ml B1

The PH will assumably be higher than in the original due to the TEA.
Add the metabisulphate (Z1) in 1 ml increments until PH drops to about 8.3.
Each shot will add 0.025g sodium metabisulphate.

Develop a test strip.

Experiment 3

If anything turns out to be wrong with the highlights, experiment with Z2 - potassium bromide.