Increasing concentration of developer formula

Jesse K · Oct 20, 2021

I recently acquired a copy of Steve Anchell's The Darkroom Cookbook to search for some chemically-safe (no dermatitis, toxic reactions, allergens, etc.) developer formulas to use in beginner workshops or to include in kits. Chris Patton's E-72 developer is described as an "environmentally friendly Dektol-type developer," as it substitutes Phenidone for metol and ascorbic acid for hydroquinone. Here is the formula:

Water at 125F/52C, 750.0 mL
Phenidone, 0.3 g
Sodium sulfite, anhydrous, 45.0 g
Ascorbic acid, 19.0 g
Sodium carbonate, monohydrate, 90.0 g
Potassium bromide, 1.9 g
Water to make 1.0 liter

Dilute 1:1

QUESTION: How would I go about increasing the concentration of the stock solution so that I could make the same quantity of developer without a full liter of stock solution? I'd prefer something similar to Ilford's Multigrade, which I believe is a 1+9 ratio, and a 500 mL bottle goes a very long way.

Another thing: I'm a little concerned about possible transport/legal/environmental restrictions around potassium bromide, so if anyone cares to suggest any possible substitutes, I would appreciate it.

Thank you all!

osella · Oct 20, 2021

There are others who could answer your question better, but it would depend on the solubility of each different component.

I would look at PC-TEA as well, as it has almost the exact same components and is made as a concentrate similar to HC-110. https://www.photrio.com/forum/threads/formula-for-pc-tea-developer.3748/

removed account4 · Oct 20, 2021

Steve Anchell has a website I think called the https://www.darkroomcookbook.com/
you might register there and ask there / him
sorry to send you "away" but I figure might ask the source

John

ps. if / when you find out please report back and update your thread ?

Lachlan Young · Oct 20, 2021

Adox Neutol Eco or Moersch eco 4812 is going to be a better answer rather than that book of errant & strongly held opinions and often flawed transcriptions of formulae. And do look up Ilford's safety guidelines - they are more succinct and accurate than the ignorant yet populist 'hygiene theatre' that surrounds so much photochemistry - there are many things that people interact with on a daily basis that (seemingly unknown to them) are massively more dangerous.

The formula you posted has an immediately obvious & significant issue - specifically, it tries to ignore the Fenton reaction.

Jesse K · Oct 20, 2021

jnantz said:
Steve Anchell has a website I think called the https://www.darkroomcookbook.com/
you might register there and ask there / him
sorry to send you "away" but I figure might ask the source

John

ps. if / when you find out please report back and update your thread ?

No worries! That’s a good idea. I’ll go check it out. If need be, I could even reach out to Steve through the contact information on his website/professorial page. I’ll be sure to update my post with my findings!

Thanks,
Jesss

Jesse K · Oct 20, 2021

Lachlan Young said:
Adox Neutol Eco or Moersch eco 4812 is going to be a better answer rather than that book of errant & strongly held opinions and often flawed transcriptions of formulae. And do look up Ilford's safety guidelines - they are more succinct and accurate than the ignorant yet populist 'hygiene theatre' that surrounds so much photochemistry - there are many things that people interact with on a daily basis that (seemingly unknown to them) are massively more dangerous.

The formula you posted has an immediately obvious & significant issue - specifically, it tries to ignore the Fenton reaction.

I agree with you on the Ilford safety guidelines. While I know that the vast majority of these chemicals are safer than most things we encounter in daily life, I can’t take that risk with youngsters that I might be working with, or even adult beginners who may have unknown allergies/sensitivity to hydroquinone, metol, etc. I’ll check out the formulas you mentioned though!

Additionally, would you care to elaborate on the Fenton reaction? I’m pretty new to photochemistry, so forgive my ignorance.

Thank you,
Jess

koraks · Oct 21, 2021

Jesse K said:
How would I go about increasing the concentration of the stock solution so that I could make the same quantity of developer without a full liter of stock solution?

Start with replacing the sodium carbonate and sodium sulfite with potassium carbonate and potassium sulfite. It will increase costs, but the potassium versions are more soluble. Otherwise it's a pretty straightforward exercise of increasing concentration. I'm not sure if 10x as concentrated will work without further modification (apart from the sodium -> potassium change), but > 5x as strong should work easily.

Jesse K said:
transport/legal/environmental restrictions around potassium bromide

Can't tell for sure, but there's no real safety concern here.

Jesse K said:
Additionally, would you care to elaborate on the Fenton reaction?

I'll leave that up to @Lachlan Young, but the issue is that dissolved iron (even trace amounts) triggers a chain reaction that basically destroys the ascorbate. It can happen fairly quickly, in a matter of hours, and you don't notice it until trying to develop some paper/film and find that the developer is as dead as a doornail.
Hence, the choice of an ascorbate developer for a concentrated stock is not an obvious one, and may be technically virtually impossible to get to work reliably (if storage times of days, weeks, months are needed)!

Alan Johnson · Oct 21, 2021

https://www.photrio.com/forum/threads/metol-ascorbate-keeping-properties.75541/#post-1044993
This was my effort at a simple ascorbate concentrate. It is limited by the amount of sodium sulfite that can conveniently be dissolved.
There is also the similar DS-12 which contains also triethanolamine and salicylic acid to minimise the Fenton reaction if you can be bothered to get them.
https://web.archive.org/web/2008093...er_Recommendations#DS-10_Fine_grain_developer

Tom Kershaw · Oct 21, 2021

Alan Johnson said:
There is also the similar DS-12 which contains also triethanolamine and salicylic acid to minimise the Fenton reaction if you can be bothered to get them.

DS-12 works very well prepared as a 5x concentrate - the salicylic acid will go into solution eventually. Somewhere on Photrio there is a reference to preparing a 10x concentrate of DS-12, although this was accomplished with a magnetic stirrer.

Nikola Dulgiarov · Oct 21, 2021

There is a good reason no concentrated liquid ascorbate film developer is available from a commercial source - they are unstable even with the best efforts to stabilize them with inhibitors of the Fenton reaction and other antioxidants. Agfa produced, and perhaps there are similar formulas available, an ascorbate print developer, one variant of their Neutol series, but print developers have the advantage that even if they lose activity, you won't lose the negative in the process. There are patents for concentrated ascorbate print developers, see the attached files.

Compound A is Dimezone-S or Phenidone. The patent purports improved stability, though some have doubts about DTPA's ability to preserve ascorbate developers. I would add Dequest 2010 (aka HEDP, HEDPA, etidronic acid, etc) at about 2g/L.
The acetic acid is probably used to fine-tune the pH. You can decrease the potassium carbonate by 30g to achieve the same pH, and I would add about 20g of sodium bicarbonate (baking soda), to balance the ionic strength. This would lower the pH slightly and might even make the benzotriazole unnecessary.

I think a better approach would be to prepare powder formulas that you dissolve as needed. If diluted with distilled water, they should be useful for the duration of a printing session. A ready-to-dissolve package for a convenient size (0.5-1-2L) is about as convenient as measuring out a 1+9 concentrate. Powders dissolve fairly quickly. You could for example prepare Suzuki's DS-14 print developer, omitting the salicylic acid and TEA (or leave in the salicylic acid for increased open tray life), as a powder formula, which should be stable even as a single-part formulation. The E72 recipe on the first post uses, IMO, too much alkali, which is OK for buffering, but might introduce trace metals, which are detrimental to tray life.

Donald Qualls · Oct 21, 2021

Nikola Dulgiarov said:
There is a good reason no concentrated liquid ascorbate film developer is available from a commercial source - they are unstable even with the best efforts to stabilize them with inhibitors of the Fenton reaction and other antioxidants.

This is why I'd recommend a waterless concentrate developer rather than increasing concentration of a conventional one, at least with ascorbate formulae. Kodak has managed to make stock strength Xtol last well, and EcoPro does (by copying Kodak's expired patents, I'm sure). Most recently, Adox has offered XT-3 which eliminates the borate alkali in the Kodak and LegacyPro products -- but Mytol is no longer recommended for mixing and storing stock; instead, "instant Mytol" is the preferred, um, solution.

What I'd suggest, rather than trying to mix a super-strength stock solution (a method that does work with MQ and PQ developers, BTW, within solubility limits) is to make up premeasured dry chemical packets: developing agents in one, preservative and alkali another, or developing agents and preservative on one and just alkali in the other. Mixing at working strength eases dissolution of the dry chemicals (more water than stock), so with PC mixes you should be able to avoid having to heat the water, then wait for it to cool before developing. It'll take a few minutes longer to mix your working solution this way than it would from stock solution, but you'll never have to be concerned about Fenton ruining your day.

Raghu Kuvempunagar · Oct 21, 2021

OP:

Make it a two part concentrated print developer.

First, taking cue from Mocon, which is a highly concentrated substitute for XTol, you can make a Part A that has only Phenidone and Ascorbic acid in the required quantities (i.e., 10X of the weights in your formula) and also Metaborate. Go through the resource page on Mocon I linked, it should give you very good idea of how to go about making Part A. Next, move Carbonate, Sulphite and Bromide in your formula to Part B. Use Potassium salts in place of Sodium Salts and you should be able to get concentrated Part B. Maybe you can even cut down significant amount of Carbonate due to the Metaborate present in Part A.

With this two part concentrated developer, there is no need to worry about Fenton reaction as long as you're going to use the working solution as soon as you mix it from the concentrates.

drmoss_ca · Oct 21, 2021

Talking of safety, it always amused me that paraphenylene diamine (CD-4 in the C-41 process) was voted Contact Allergen of the Year in 2006 by the American Contact Dermatitis Society. The same stuff people who dye their hair rub into their scalps every couple of weeks.

Lachlan Young · Oct 21, 2021

drmoss_ca said:
Talking of safety, it always amused me that paraphenylene diamine (CD-4 in the C-41 process) was voted Contact Allergen of the Year in 2006 by the American Contact Dermatitis Society. The same stuff people who dye their hair rub into their scalps every couple of weeks.

PPD and CD-3/ CD-4 differ very radically in their ability to cause dermatitis/ sensitisation. In essence this was the reason why Kodak put so much effort into creating them in the mid 20th century - and given this, the fact that people still willingly apply raw PPD to their person today is slightly astounding.

Alan Johnson · Oct 21, 2021

drmoss_ca said:
Talking of safety, it always amused me that paraphenylene diamine (CD-4 in the C-41 process) was voted Contact Allergen of the Year in 2006 by the American Contact Dermatitis Society. The same stuff people who dye their hair rub into their scalps every couple of weeks.

Need to distinguish between PPD and CD-4:
https://www.photrio.com/forum/threads/replace-ppd-by-cd-3.68079/page-2#post-960239

mohmad khatab · Oct 21, 2021

PG110B
--------------
Propylene glycol mono............ 50 ml
Borax........................................ 30 g
Ascrobic acid ........................... 10 g
phenideone .............................. 1 g
Propylene glycol>>>>>>>>>>>100 ml
dllute for film 1:100 = D76 stock - for peper >>> 1:25 = deketol

Raghu Kuvempunagar · Oct 22, 2021

drmoss_ca said:
Talking of safety, it always amused me that paraphenylene diamine (CD-4 in the C-41 process) was voted Contact Allergen of the Year in 2006 by the American Contact Dermatitis Society.

After reading this I got curious about contact allergen of other years and found that 1) Propylene Glycol (2018) and 2) Gold (2001) are also in the list. Interestingly, Wikipedia page on this award says that the award has dubious distinction. Now, Wikipedia itself has dubious distinction and hence not sure what to make of the award.

john_s · Oct 22, 2021

Raghu Kuvempunagar said:
OP:

Make it a two part concentrated print developer.

First, taking cue from Mocon, which is a highly concentrated substitute for XTol, you can make a Part A that has only Phenidone and Ascorbic acid in the required quantities (i.e., 10X of the weights in your formula) and also Metaborate. Go through the resource page on Mocon I linked, it should give you very good idea of how to go about making Part A. Next, move Carbonate, Sulphite and Bromide in your formula to Part B. Use Potassium salts in place of Sodium Salts and you should be able to get concentrated Part B. Maybe you can even cut down significant amount of Carbonate due to the Metaborate present in Part A.

With this two part concentrated developer, there is no need to worry about Fenton reaction as long as you're going to use the working solution as soon as you mix it from the concentrates.

To reduce the carbonate you can use a little sodium hydroxide. It is very soluble and extremely alkaline. An example is Ian Grant's concentrated ID-78 at lostlabours.co.uk. For ID-78 I have found 3x normal concentration is possible with molar equivalent potassium carbonate (instead of sodium carbonate), but I might try the hydroxide trick next time. I've also seen hydroxide in MSDS docs for developers (Agfa maybe). I don't mean Rodinal.

Donald Qualls · Oct 22, 2021

Problem with NaOH in place of carbonate is that even at low concentrations, the pH will be higher than spec and development will be faster, grain larger, etc. This can be partially corrected by mixing the sodium hydroxide with borax (poor man's Kodalk aka sodium metaborate); that gives a pH higher than borax, but much lower than NaOH (not quite the same as carbonate, but closer than NaOH without buffering).

Raghu Kuvempunagar · Oct 22, 2021

Based on the idea of Mocon for a concentrated Part A and @john_s's suggestion of using a combination of Potassium carbonate and Sodium hydroxide in Part B instead of Sodium carbonate, here's a two part formula for OP to consider:

Part A:
Propylene glycol 750ml
Sodium metaborate 4 mol 82 g
Ascorbic acid 190 g
Phenidone 3 g
Propylene glycol to make 1l

Ratio of Metaborate to Ascorbic Acid is same as in Mocon. Propylene glycol is in excess to get a easy to use volume.
1l of Part A can be used in making 20l of working solution.

Part B:
Sodium sulfite ah 112.5 g
Potassium carbonate ah 72g
Sodium hydroxide 4g
Potassium bromide 4.75 g
Water to make 1.0 liter

Sodium carbonate is substituted by a combination of Potassium carbonate and Sodium hydroxide as suggested by ID-78.
1l of Part B can be used to making 5l of working solution.

To get the 'equivalent' of the working solution of OP's developer at dilution 1:1, use 50ml of Part A + 200ml of Part B + Water to make 1l. Small adjustment to the amount of Sodium hydroxide might be needed to get strictly same pH as OP's working solution.

Raghu Kuvempunagar · Oct 22, 2021

michael_r said:
As long as there is no difficulty dissolving the Phenidone in p-glycol at a non-alkaline pH, I'd suggest leaving out the metaborate to simplify. (dissolving the Phenidone before the ascorbic acid would likely help). Then skip the hydroxide in part B and just use as much carbonate as you reasonably can. Target pH of working solution should be in the 10.5 range.

Metaborate is rather necessary in Part A to get all of that Ascorbic Acid into Propylene Glycol. This is discussed in the Mocon resource page and in some other threads. Apparently Borates form esters with Glycol which increases solubility of Ascorbic Acid. Quoting @albada: "Dissolving some sodium metaborate into propylene glycol increases the amount of ascorbic acid that can be dissolved. Or it at least makes it easier for ascorbic acid to dissolve. This fact allows the concentration to be high. Using Mocon as an example, when you pour the ascorbic acid into the solution, it'll seem impossible that such a large amount of powder could dissolve in that small amount of liquid. But it will. In fact, there seems to be no solubility-limit. That, plus the fact that freezing produces no precipitation, tells me that ascorbic acid is combining with propylene glycol in some way, as also occurs with sodium metaborate."

john_s · Oct 22, 2021

Donald Qualls said:
Problem with NaOH in place of carbonate is that even at low concentrations, the pH will be higher than spec and development will be faster, grain larger, etc. This can be partially corrected by mixing the sodium hydroxide with borax (poor man's Kodalk aka sodium metaborate); that gives a pH higher than borax, but much lower than NaOH (not quite the same as carbonate, but closer than NaOH without buffering).

You would certainly want to control the amount of NaOH accurately in order to ensure that pH was at the desired level.

Assuming that that was done, would there be any downside, such as instability or inferior buffering? I haven't tried it with a developer, I'm just citing Ian Grant's method.

Donald Qualls · Oct 22, 2021

john_s said:
You would certainly want to control the amount of NaOH accurately in order to ensure that pH was at the desired level.

Assuming that that was done, would there be any downside, such as instability or inferior buffering? I haven't tried it with a developer, I'm just citing Ian Grant's method.

Given there's other alkali present, it's just a matter of controlling the pH of the buffer system they create together. A pH meter can be had for not much money from Amazon.

Raghu Kuvempunagar · Oct 22, 2021

Raghu Kuvempunagar said:
Based on the idea of Mocon for a concentrated Part A and @john_s's suggestion of using a combination of Potassium carbonate and Sodium hydroxide in Part B instead of Sodium carbonate, here's a two part formula for OP to consider:

Part A:
Propylene glycol 750ml
Sodium metaborate 4 mol 82 g
Ascorbic acid 190 g
Phenidone 3 g
Propylene glycol to make 1l

Ratio of Metaborate to Ascorbic Acid is same as in Mocon. Propylene glycol is in excess to get a easy to use volume.
1l of Part A can be used in making 20l of working solution.

Part B:
Sodium sulfite ah 112.5 g
Potassium carbonate ah 72g
Sodium hydroxide 4g
Potassium bromide 4.75 g
Water to make 1.0 liter

Sodium carbonate is substituted by a combination of Potassium carbonate and Sodium hydroxide as suggested by ID-78.
1l of Part B can be used to making 5l of working solution.

To get the 'equivalent' of the working solution of OP's developer at dilution 1:1, use 50ml of Part A + 200ml of Part B + Water to make 1l. Small adjustment to the amount of Sodium hydroxide might be needed to get strictly same pH as OP's working solution.

If Sodium Metaborate is difficult to source where you are, it can be synthesized easily using Borax and Sodium Hydroxide. Details are in this post: https://www.photrio.com/forum/threads/kodak-sodium-metaborate.186175/#post-2456701

Raghu Kuvempunagar · Oct 23, 2021

Raghu Kuvempunagar said:
If Sodium Metaborate is difficult to source where you are, it can be synthesized easily using Borax and Sodium Hydroxide. Details are in this post: https://www.photrio.com/forum/threads/kodak-sodium-metaborate.186175/#post-2456701

As Metaborate is needed in the two parts print developer only for the purpose of dissolving Ascorbic Acid into Propylene Glycol, it should be possible to substitute it in Part A by Borax. If I were to brew this print developer, I would use just enough Borax that would get all the Ascorbic Acid into solution.

Increasing concentration of developer formula

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