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.
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 resultHow 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 View attachment 335044View attachment 335045
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!
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!
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.
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) :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.
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.
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?
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.
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.
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 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
Excellent info. Thanks.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
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.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?