FX-37 with two solutions

bluechromis · Oct 28, 2022

I want to mix up a batch of Crawley's FX-37 developer (See recipe below). Anchell and Troop say the FX-37 stock solution should not be kept longer than three months. Since it is not my main developer, it would useful have the greatest shelf life. I have heard that developers last longer if the alkali is put in a separate solution from the other ingredients. So you have a solution A and solution B that are added together to make the working solution. It seems like Spur may do that with some of their developers. I am wondering how this could work with FX-37. The original recipe results in 1 L of stock. Would it make sense to mix the borax and carbonate up in 500 ml water and the other ingredients in 500 ml water and two combined 1+1 when making the working solution? Would there be a better way to do it? Would there be any benefit to putting some of the sulfite with the alkali as a preservative?

Distilled water (50°C) ................. 750 ml
Sodium sulfite (anhy) .................. 60.0 g
Hydroquinone ........................... 5.0 g
Sodium carbonate (anhy) ................ 5.0 g
Phenidone .............................. 0.5 g
Borax .................................. 2.5 g
Potassium bromide ...................... 1.0 g
Distilled water to make ................ 1.0 L

koraks · Oct 28, 2022

bluechromis said:
Would it make sense to mix the borax and carbonate up in 500 ml water and the other ingredients in 500 ml water and two combined 1+1 when making the working solution?

Should work, yes.

bluechromis said:
Would there be a better way to do it?

Probably. One thing to start with would be to make the solutions as concentrated as you can, observing the solubility limits of the compounds in it. Generally this helps to keep oxidation limited as well. It's particularly relevant for the stock that contains the developing agents.

Another avenue would be to replace the water with a solvent that's less prone to absorb oxygen from the air (or already contain it, such as tap water). Polypropylene glycol comes to mind, but I don't know if hydroquinone is soluble in it. You'd have to look that up.

albada · Oct 28, 2022

Nine years ago, I created a concentrated developer based on propylene glycol (PG), so I have notes on it. My notes tell me that at least 200 g of hydroquinone will dissolve in a liter of PG. Strangely, sodium metaborate and borax also dissolve in PG, even though they are salts. In PG, their form changes (I forget the name), enabling them to dissolve. In the formula in posting #1, you could dissolve hydroquinone, phenidone, and borax in PG. But borax and sodium metaborate contain much water, so it might be better to not dissolve them in PG, reserving PG for only the developers. A bottle of my concentrate has been stored in my freezer for 8 years, and it's still fine, so I recommend PG-based concentrates.

John Wiegerink · Oct 29, 2022

bluechromis said:
I want to mix up a batch of Crawley's FX-37 developer (See recipe below). Anchell and Troop say the FX-37 stock solution should not be kept longer than three months. Since it is not my main developer, it would useful have the greatest shelf life. I have heard that developers last longer if the alkali is put in a separate solution from the other ingredients. So you have a solution A and solution B that are added together to make the working solution. It seems like Spur may do that with some of their developers. I am wondering how this could work with FX-37. The original recipe results in 1 L of stock. Would it make sense to mix the borax and carbonate up in 500 ml water and the other ingredients in 500 ml water and two combined 1+1 when making the working solution? Would there be a better way to do it? Would there be any benefit to putting some of the sulfite with the alkali as a preservative?

Distilled water (50°C) ................. 750 ml
Sodium sulfite (anhy) .................. 60.0 g
Hydroquinone ........................... 5.0 g
Sodium carbonate (anhy) ................ 5.0 g
Phenidone .............................. 0.5 g
Borax .................................. 2.5 g
Potassium bromide ...................... 1.0 g
Distilled water to make ................ 1.0 L

I thought about doing this with FX-37 back several years ago, but never attempted it. I stopped using FX-37 when I became addicted to Pyrocat developers and replenished Xtol. I used FX-37 with Ilford Delta 100, and it worked extremely well.

Alan Johnson · Oct 29, 2022

FX-2 High Acutance Film Developer

web.archive.org

Here's a 2-solution with an estimated life of the Part A of 1 year, so it seems likely that the OP's 2 solution should be similarly long lasting. It could probably be made to last longer still by adding bisulfite to the part A, as with the PMK Pyro developer. This reduces the number of ions floating around waiting to be oxidized. It might have an effect on the required development times.

bluechromis · Oct 30, 2022

Alan Johnson said:
FX-2 High Acutance Film Developer

FX-2 High Acutance Film Developer

web.archive.org

Here's a 2-solution with an estimated life of the Part A of 1 year, so it seems likely that the OP's 2 solution should be similarly long lasting. It could probably be made to last longer still by adding bisulfite to the part A, as with the PMK Pyro developer. This reduces the number of ions floating around waiting to be oxidized. It might have an effect on the required development times.

Thanks.

bluechromis · Oct 30, 2022

koraks said:
Should work, yes.

Probably. One thing to start with would be to make the solutions as concentrated as you can, observing the solubility limits of the compounds in it. Generally this helps to keep oxidation limited as well. It's particularly relevant for the stock that contains the developing agents.

Another avenue would be to replace the water with a solvent that's less prone to absorb oxygen from the air (or already contain it, such as tap water). Polypropylene glycol comes to mind, but I don't know if hydroquinone is soluble in it. You'd have to look that up.

bluechromis · Oct 30, 2022

Thanks Koraks. Indeed my most used developers are formulated in glycol/TEA. That approach makes a lot of sense to me. Instead of using gobs of preservative to reduce oxidation of developing agents, better to not let much oxygen in in the first place. I assume that part of the basis of HC-110's great shelf life is because it uses a non-aqueous solvent. I remember Pat Gainer saying that if he were to work with FX-37 he would strive to replace the hydroquinone with ascorbate and put it in an organic solvent. At this point, I am going evaluate FX-37 for use in certain projects and see if has benefits better than my organic solvent developers, or one of the ascorbate developers that are mixed from bulk chems for immediate use.

bluechromis · Oct 30, 2022

John Wiegerink said:
I thought about doing this with FX-37 back several years ago, but never attempted it. I stopped using FX-37 when I became addicted to Pyrocat developers and replenished Xtol. I used FX-37 with Ilford Delta 100, and it worked extremely well.

Thanks John.

FX-37 with two solutions

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