New HC-110 Formula

[alanrockwood]

The main carrier for sulfite in c110 was diethanolamine sulfur dioxide (DESO). It is not available commercially so I make this regularly at home when I want to concoct hc110 concentrate (about as close as I can get reverse-engineering it). DESO can easily be made from diethanolamine and sulfur dioxide. It is stable and has very little odor once made. Best make it out of doors even if you have a SO2 scrubber as part of your setup.

How do you make the SO2? I can think of perhaps sulfite plus acid, which should produce SO2 bubbling off, or by burning sulfur. The first method would have a lot of water contamination in the gas, but is probably more controllable than burning some sulfur to make SO2. Can you enlighten us about your setup?

 

[doctorpepe]

How do you make the SO2? I can think of perhaps sulfite plus acid, which should produce SO2 bubbling off, or by burning sulfur. The first method would have a lot of water contamination in the gas, but is probably more controllable than burning some sulfur to make SO2. Can you enlighten us about your setup?

Sulfuric acid 33% slowly added to sodium sulfite (first bottle) in a closed system. Bubble it through a 99+% diethanolamine (2nd bottle). Third bottle is a scrubber that captures any overflow SO2 so there’s minimal release. Takes a few hours on a Saturday afternoon the grad cylinder shows the final result

 

[Anon Ymous]

Sulfuric acid 33% slowly added to sodium sulfite (first bottle) in a closed system. Bubble it through a 99+% diethanolamine (2nd bottle). Third bottle is a scrubber that captures any overflow SO2 so there’s minimal release. Takes a few hours on a Saturday afternoon the grad cylinder shows the final result View attachment 335044 View attachment 335045

Awesome!

 

[doctorpepe]

How do you make the SO2? I can think of perhaps sulfite plus acid, which should produce SO2 bubbling off, or by burning sulfur. The first method would have a lot of water contamination in the gas, but is probably more controllable than burning some sulfur to make SO2. Can you enlighten us about your setup?

Just some more hc110 drivel;

There is no triethanolamine in hc110. None of the old patents cite it. Lots of DI-Ethanolamine. I have experimented with adding some triethanolamine to a formulated concentrate and it just makes it a bit more active (higher gamma in the finished product or slightly shorter times to achieve equivalent gamma) which would make sense as triethanolamine is slightly more alkaline than di- and should have the expected resulted cited above.

I prefer to keep it closer to the original formulation and, if I need more developer activity, add an alkali to the water when I dilute the syrup.

Other commented that they have found “lumps” in their hc110. Not sure what that is as I’ve never encountered it. It is not likely to be “frozen” diethanolamine because, even though it “freezes” under about 75F, the hc110 formula calls for both ethylene glycol and diethylene glycol (which might be familiar to others as parts of standard “antifreeze”).

I am pleased that ilford offers a very good hc110 replacement but I still have the capacity to make my own at home when I have the time and I have reverse engineered a formula that is, in all likelihood, very close to the original. There is NO water in the original which is why it has such a long shelf life. The original Kodak hc110 has a lot of water and this will oxidize rapidly in storage.

Why do I like hc110? For all the reasons cited already. I am semi retired and downsized my large darkroom to shared space in our spare bathroom. My dear wife didn’t want an armamentum of bunches of chemicals in the bathroom linen closet and accepts that I like to process 120 and 8x10 stuff from time to time. The hc110 concept saves space and provides consistent results. I keep the glass plates, collodion & silver nitrate baths in the garage out of reach!

 

[alanrockwood]

Just some more hc110 drivel;

There is no triethanolamine in hc110. None of the old patents cite it. Lots of DI-Ethanolamine. I have experimented with adding some triethanolamine to a formulated concentrate and it just makes it a bit more active (higher gamma in the finished product or slightly shorter times to achieve equivalent gamma) which would make sense as triethanolamine is slightly more alkaline than di- and should have the expected resulted cited above.

I prefer to keep it closer to the original formulation and, if I need more developer activity, add an alkali to the water when I dilute the syrup.

Other commented that they have found “lumps” in their hc110. Not sure what that is as I’ve never encountered it. It is not likely to be “frozen” diethanolamine because, even though it “freezes” under about 75F, the hc110 formula calls for both ethylene glycol and diethylene glycol (which might be familiar to others as parts of standard “antifreeze”).

I am pleased that ilford offers a very good hc110 replacement but I still have the capacity to make my own at home when I have the time and I have reverse engineered a formula that is, in all likelihood, very close to the original. There is NO water in the original which is why it has such a long shelf life. The original Kodak hc110 has a lot of water and this will oxidize rapidly in storage.

Why do I like hc110? For all the reasons cited already. I am semi retired and downsized my large darkroom to shared space in our spare bathroom. My dear wife didn’t want an armamentum of bunches of chemicals in the bathroom linen closet and accepts that I like to process 120 and 8x10 stuff from time to time. The hc110 concept saves space and provides consistent results. I keep the glass plates, collodion & silver nitrate baths in the garage out of reach!

That's an excellent writeup. However, could you clear up the ambiguity where you said "There is NO water in the original which is why it has such a long shelf life. The original Kodak hc110 has a lot of water and this will oxidize rapidly in storage." First you said that there is no water in the original, and then that there is a lot of water in the original.

Also, do you have an idea how much water your scheme transfers to the diethanolamine? I know that concentrated H2SO4 is a strong dehydrating agent, but is 33% H2SO4 a high enough concentration to keep water from significantly contaminating the gas being produced?

Would there be any merit to inserting some kind of water trap before the gas reaches the chamber containing diethanolamine?

Do you run the process until the solution reaches saturation in SO2? In other words, do adjust the amount of sodium sulfite in excess of the amount needed to nominally saturate the solution with SO2 in order to be sure that saturation is reached? Or perhaps saturation of the solution is not the goal(?).

 

[bnxvs]

Just some more hc110 drivel;

There is no triethanolamine in hc110. None of the old patents cite it. Lots of DI-Ethanolamine. I have experimented with adding some triethanolamine to a formulated concentrate and it just makes it a bit more active (higher gamma in the finished product or slightly shorter times to achieve equivalent gamma) which would make sense as triethanolamine is slightly more alkaline than di- and should have the expected resulted cited above.

I prefer to keep it closer to the original formulation and, if I need more developer activity, add an alkali to the water when I dilute the syrup.

Other commented that they have found “lumps” in their hc110. Not sure what that is as I’ve never encountered it. It is not likely to be “frozen” diethanolamine because, even though it “freezes” under about 75F, the hc110 formula calls for both ethylene glycol and diethylene glycol (which might be familiar to others as parts of standard “antifreeze”).

I am pleased that ilford offers a very good hc110 replacement but I still have the capacity to make my own at home when I have the time and I have reverse engineered a formula that is, in all likelihood, very close to the original. There is NO water in the original which is why it has such a long shelf life. The original Kodak hc110 has a lot of water and this will oxidize rapidly in storage.

Why do I like hc110? For all the reasons cited already. I am semi retired and downsized my large darkroom to shared space in our spare bathroom. My dear wife didn’t want an armamentum of bunches of chemicals in the bathroom linen closet and accepts that I like to process 120 and 8x10 stuff from time to time. The hc110 concept saves space and provides consistent results. I keep the glass plates, collodion & silver nitrate baths in the garage out of reach!

If I may, I would correct your arguments a little bit. Triethanolamine has less basicity than diethanolamine. And the greater basicity of its adduct in solution is due to the fact that its adduct is more susceptible to hydrolysis than the adduct of diethanolamine.
Experimentally established the fact that "With increasing basicity in the series of ethanolamines (triethanolamine - diethanolamine - monoethanolamine) their absorptive capacity relative to SO2 increases. The transition from monoethanolamine to N-methylmonoethanolamine is accompanied by an increase in the base pKa value, but there is a decrease in its absorption capacity."
(series: monoethanolamine - diethanolamine - triethanolamine - N-methylmonoethanolamine)

p.s. Here is a good list of literature on the subject: https://link.springer.com/article/10.1134/S1070363216080065

 

[doctorpepe]

I am glad my reply stimulated some excellent discussions.

I wrote in haste when I said “the original HC110 has a lot of water in it”. The NEW formulation has water. The original none.

I don’t know how much water my scheme transfers to the diethanolamine and I guess I could add a dehydrator to it but I am not aiming for this level of purity!

I have some literature that gives the pH if diethanolamine as 9.8 and triethanolamine as 10.5. I have not tested this so if I am in error, I stand corrected.

I adjust the amount of sodium sulfite to produce enough SO2 to convert all the DE to DESO2. I have the values in the lab but not immediately at hand. Can look them up later on and post. I don’t run any quantitative analyses on my products so I can’t give any more data on the exact percentages of things.

It is possible that the use of 33% sulfuric acid (readily available battery acid) could introduce water. I could get 98% sulfuric acid but just didn’t have any on hand.

The other ingredients I used are consistent with Kodak’s patent and with the older msds (which doesn’t include some more esoteric chemicals). Dilutions and developing times seem to work well with trix, ilford fp4 & hp5 at 1:31, 1:63. (No data on other films or dilutions. )

 

[MattKing]

I wrote in haste when I said “the original HC110 has a lot of water in it”. The NEW formulation has water. The original none.

Which "NEW" one?
The short-lived 2019 made in the USA version, or the current Sino Promise one that appears to be coming from both Germany and China?

 

[bnxvs]

I am glad my reply stimulated some excellent discussions.

...

I don’t know how much water my scheme transfers to the diethanolamine and I guess I could add a dehydrator to it but I am not aiming for this level of purity!

I have some literature that gives the pH if diethanolamine as 9.8 and triethanolamine as 10.5. I have not tested this so if I am in error, I stand corrected.

In this matter in general, everything is complicated. Many sources contradict each other, strange as it may seem. Here is my data, which I usually use (in pKb) :
TEA (triethanolamine) -- pKb=6.24
DEA (diethanolamine) -- pKb=5.04

So a 0.1M TEA solution should give these pH results:
pH 10.3
pOH 3.7
[H+] 5.0e-11
[OH-] 0.0002

and DEA:
pH 11.0
pOH 3.0
[H+] 1.1e-11
[OH-] 0.00095

At the same time, the source I cited gave such data:
TEA (triethanolamine) (pKa 7.80) - i.e. pKb = 14 - 7.8 = 6.2 (сalculated pH 10.4)
DEA (diethanolamine) (pKa 8.80) - i.e., pKb = 14 - 8.8 = 5.2 (calculated pH 10.9)

In other sources I have encountered other data. I don't know what it has to do with it. Maybe I don't understand something. I am not a chemist, unfortunately. I always have to determine the pH experimentally, by measuring. And I use calculations only to determine general, approximate parameters of reactions.

p.s. Have you tried weighing the flask with DEA before bubbling and after to determine the mass fraction of absorbed SO2?

p.p.s. Here's some data on the various photoreagents I've been able to collect : https://telegra.ph/PkaPkb-11-25

 

[Anon Ymous]

It is possible that the use of 33% sulfuric acid (readily available battery acid) could introduce water. I could get 98% sulfuric acid but just didn’t have any on hand.

The reaction of sodium sulfite with sulfuric acid produces water anyway. I don't know how much of a difference using 98% acid would make.

 

[alanrockwood]

The reaction of sodium sulfite with sulfuric acid produces water anyway. I don't know how much of a difference using 98% acid would make.

One difference could be that 98% sulfuric acid is a very strong dehydrating agent, which means that it is going to prevent water vapor from leaving the solution and contaminating the gas phase SO2. (It's not perfect, so there will be a little bit of water vapor produced, but very little. Most of it will remain stuck in the liquid.)

33% sulfuric acid will be a less efficient dehydrating agent. I do not know how much less efficient, but in any case it will allow more water to escape into the vapor phase and ultimately into the diethanolamine solution. Is it enough water to matter? I don't know.

One thing that might help is to cool the sodium sulfite and the sulfuric acid solution before they are combined. This will lower the vapor pressure of the water by several fold, in comparison to running the setup at room temperature or higher. This of course also depends on the temperatures of the cooled reagents. There are some additional subtleties I won't go into here, so it's probably not quite as simple as I am presenting it, but I think that basically cooling the reagents (and the reaction vessel) would likely produce a purer stream of SO2, i.e. with less water contamination in the diethanol amine/SO2 solution.

One of many things I don't know is just how much water can the HC-110 concentrate tolerate before it loses its famous long lifetime.

As an aside, when nitric acid is used to nitrate materials to make explosives and propellants, like nitroglycerine and guncotton, concentrated H2SO4 is included along with the nitric acid. The main purpose of including H2SO4 is because it is a strong drying agent which therefore prevents the water formed during the nitration process from causing problems in the reaction.

 

[Anon Ymous]

One thing that might help is to cool the sodium sulfite and the sulfuric acid solution before they are combined.

So, perhaps keeping the sodium sulfite vessel in an ice bath?

EDIT: What drying agent could be used, that wouldn't react with SO2?

 

[bnxvs]

I think the hydration factor of the DEA adduct can in principle be neglected. Firstly, little water is released to significantly affect the properties of the adduct obtained, and secondly, the final composition of HC-110 contains ethylene glycol and diethylene glycol, which themselves are very good dryers. On this basis, it seems to me, this factor is negligible.

p.s. However, no one prevents to pass the resulting SO2 through an additional vessel with concentrated H2SO4.

 

[bnxvs]

@ doctorpepe:
Actually, it would be very nice if you could weigh your product before and after saturating it with SO2, as well as measure the pH of the aqueous solution of your adduct. For example, 10 g per 100 ml of water.
This would be very helpful to understand the subtleties of the process and to calculate the various possible characteristics.

 

[bnxvs]

And a little humor: Scientists have found that very good absorption characteristics with respect to SO2 have chicken manure, purified by water washing. Almost 5 g SO2 per 1 kg of manure.
p.s. Just don't report it to Kodak, otherwise I'm afraid to even imagine what the next modification of the HC-110 formulation will have in store for us.

 

[alanrockwood]

So, perhaps keeping the sodium sulfite vessel in an ice bath?

EDIT: What drying agent could be used, that wouldn't react with SO2?

Yes, I believe that keeping the sodium sulfite vessel in an ice bath would reduce the amount of water transferred. Cooling the 33% sulfuric acid would probably also help.

Granular anhydrous calcium sulfate is a good drying agent, and I doubt if it would react with SO2. It is the desiccant in the product product known as Drierite. There is an indicating form of Drierite that can be obtained that is blue when active and red when exhausted. If Drierite becomes exhausted it can be regenerated by spreading it out on a cookie sheet and heating it for an hour at 425F (Reference: https://secure.drierite.com/catalog3/page19b.cfm). I don't think it would be necessary to use the indicating form if one simply regenerated the anhydrous calcium sulfate prior to each use.

I think the best way to use a desiccant like Drierite would be to pack it into a column. A couple of examples are shown in the attached image. You can buy columns packed with Drierite, but I'm sure that one could make a DIY column without too much trouble.

You might be able to make granular anhydrous calcium sulfate, starting with the dihydrate of calcium sulfate in powdered form. I won't go into that in detail right now, partly because I don't know the specifics. However, I think a basic process might be to make the a plaster, let it harden/dry, break it up into granules, sift the granules (to get rid of the powder), and heat the granules to convert them anhydrous calcium sulfate.

Gypsum is one form of calcium sulfate. It is the main ingredient in sheetrock, although sheetrock contains other additives as well. However, I suspect that the other additives would probably not interfere with a DIY desiccant made from the core of some discarded sheetrock using a process similar to the one I outlined above. Of course I am somewhat guessing here.

I have focused on calcium sulfate disiccant here. There are other desiccants as well.

A cold trap is another possibility that might work as a substitute for a desiccant column or as an adjunct to a desiccant column (https://en.wikipedia.org/wiki/Cold_trap). Note: an earlier form of this post discussed a cold finger instead of a cold trap. A cold trap is what should be considered, not a cold finger. The two devices are closely related. One might think of a cold finger as an inverted cold trap.

All of this assumes that some water in the home-brew HC-110 would pose a problem. There are reasons to assume that a little bit of water wouldn't hurt the lifetime very much, but I don't know for sure. However, if it turned out that a little bit of water in the HC-110 was no problem then obviously it probably makes no sense to go to great lengths to prevent a bit of water contamination.

 

[doctorpepe]

Yes, I believe that keeping the sodium sulfite vessel in an ice bath would reduce the amount of water transferred. Cooling the 33% sulfuric acid would probably also help.

Granular anhydrous calcium sulfate is a good drying agent, and I doubt if it would react with SO2. It is the desiccant in the product product known as Drierite. There is an indicating form of Drierite that can be obtained that is blue when active and red when exhausted. If Drierite becomes exhausted it can be regenerated by spreading it out on a cookie sheet and heating it for an hour at 425F (Reference: https://secure.drierite.com/catalog3/page19b.cfm). I don't think it would be necessary to use the indicating form if one simply regenerated the anhydrous calcium sulfate prior to each use.

I think the best way to use a desiccant like Drierite would be to pack it into a column. A couple of examples are shown in the attached image. You can buy columns packed with Drierite, but I'm sure that one could make a DIY column without too much trouble.

You might be able to make granular anhydrous calcium sulfate, starting with the dihydrate of calcium sulfate in powdered form. I won't go into that in detail right now, partly because I don't know the specifics. However, I think a basic process might be to make the a plaster, let it harden/dry, break it up into granules, sift the granules (to get rid of the powder), and heat the granules to convert them anhydrous calcium sulfate.

Gypsum is one form of calcium sulfate. It is the main ingredient in sheetrock, although sheetrock contains other additives as well. However, I suspect that the other additives would probably not interfere with a DIY desiccant made from the core of some discarded sheetrock using a process similar to the one I outlined above. Of course I am somewhat guessing here.

I have focused on calcium sulfate disiccant here. There are other desiccants as well.

A cold trap is another possibility that might work as a substitute for a desiccant column or as an adjunct to a desiccant column (https://en.wikipedia.org/wiki/Cold_trap). Note: an earlier form of this post discussed a cold finger instead of a cold trap. A cold trap is what should be considered, not a cold finger. The two devices are closely related. One might think of a cold finger as an inverted cold trap.

All of this assumes that some water in the home-brew HC-110 would pose a problem. There are reasons to assume that a little bit of water wouldn't hurt the lifetime very much, but I don't know for sure. However, if it turned out that a little bit of water in the HC-110 was no problem then obviously it probably makes no sense to go to great lengths to prevent a bit of water contamination.

I manufacture the DESO by weight so I can tell you all how much so2 combines with the de.

The water bearing hc110 I am referring to is the current Kodak USA formulation with potassium sulfite and water. It is very thin and watery.

I don’t know how to remove the water vapor produced by this process. I suppose one could purify the so2 or just buy a container of so2 and run ot directly through the de.

Here is what I found on the pH of 98+% di- and Tri-ethanolamine. It looks like diethanolamine has a higher ph (11-12) than triethanolamine (11) but this may shift as one dilutes it for developing use

 

[MattKing]

The water bearing hc110 I am referring to is the current Kodak USA formulation with potassium sulfite and water. It is very thin and watery.

That isn't current anymore - it has been superseded since shortly after Sino Promise bought the business from Kodak Alaris - 2 years ago? If someone is selling that, it is quite old stock.

 

[doctorpepe]

Here is my worksheet to make DESO. It goes with the photo of the 3 bottles I use to generate so2 and capture it through the DE.

 

[bnxvs]

Thank you!

 

[doctorpepe]

Here is my worksheet to make DESO. It goes with the photo of the 3 bottles I use to generate so2 and capture it through the DE. View attachment 335557

Here is my worksheet to compile the "final product". All the ingredients are present in the original Kodak patents. The PVP was clearly cited in the Kodak patent as a good antifoggant even though it not included in the kodak MSDS. I added a bit more Catechol just because I wanted to. I opted to use Benzotriazole instead of Pot Bromide as I have found that BZT is a little bit better at suppressing fog than Bromide when Phenidone derivatives are used (some support in the literature for this too). I have a bottle I made last spring that has been about 1/8 full with minimal discoloration and still effective at making a very nice set of negatives on Ilford Ortho, FP4+ and HP5+. If I can get a good pic of the concentrate I will send it up.

 

[alanrockwood]

Here is my worksheet to make DESO. It goes with the photo of the 3 bottles I use to generate so2 and capture it through the DE. View attachment 335557

Here is my worksheet to compile the "final product". All the ingredients are present in the original Kodak patents. The PVP was clearly cited in the Kodak patent as a good antifoggant even though it not included in the kodak MSDS. I added a bit more Catechol just because I wanted to. I opted to use Benzotriazole instead of Pot Bromide as I have found that BZT is a little bit better at suppressing fog than Bromide when Phenidone derivatives are used (some support in the literature for this too). I have a bottle I made last spring that has been about 1/8 full with minimal discoloration and still effective at making a very nice set of negatives on Ilford Ortho, FP4+ and HP5+. If I can get a good pic of the concentrate I will send it up.

View attachment 335571

Excellent info. Thanks.

 

[bnxvs]

I think you did absolutely the right thing by adding catechol. I have some guesses as to why it's needed (it's just a hydroquinone isomer), but I'll keep them to myself for now, as I'm not sure of my conclusions. I also add it to my "simplified" water-based concentrate. So does PVP.

 

[relistan]

I think you did absolutely the right thing by adding catechol. I have some guesses as to why it's needed (it's just a hydroquinone isomer), but I'll keep them to myself for now, as I'm not sure of my conclusions. I also add it to my "simplified" water-based concentrate. So does PVP.

Interested in your thinking here. Is there an aspect other than as a developing agent that makes it useful?

As I understand it, in theory the catechol should both get recharged by the HQ and it in turn would do the same for the dimezone. A small amount of it would probably be directly active as HQ - catechol and some would be in the middle of an HQ - catechol - dimezone chain. Of course there is also HQ doing the same for dimezone directly. Given the speed of development by dimezone and HQ like this, and the relative slowness of HQ/catechol, I would expect that the final contribution of catechol to the resulting image would be quite small.

 

[doctorpepe]

Interested in your thinking here. Is there an aspect other than as a developing agent that makes it useful?

As I understand it, in theory the catechol should both get recharged by the HQ and it in turn would do the same for the dimezone. A small amount of it would probably be directly active as HQ - catechol and some would be in the middle of an HQ - catechol - dimezone chain. Of course there is also HQ doing the same for dimezone directly. Given the speed of development by dimezone and HQ like this, and the relative slowness of HQ/catechol, I would expect that the final contribution of catechol to the resulting image would be quite small.

Here is the year-old concentrate I made.