Well I got my new bottle today and it expires in 2023. So either Kodak is still making this stuff somewhere in the UK/EU or that the new formula is only targeted in the US due to their environment regulations, just like how Velvia 100 is discontinued.That is what my bottle looks like (USA). I bought in 2018, supposedly expired in July 2020. So far it is still good (last used in July).
If we make the assumption that the partial pressure of SO2 in the experiments in the paper was 101 bar (i.e. one atmosphere pressure) and take information from figure 1 of the paper and convert mole fraction to weight percent we would calculate that the equilibrium concentration (in percent by mass) of SO2 in DEA would be 19.2%. That's actually pretty close to the weight percent of SO2 in the old HC-110 as listed in the MSDS. Of course, DEA itself only makes up about 30-35% of the old HC-110, so the solubility of SO2 in it won't be the same as in pure DEA, but at least it may be of similar order of magnitude.I found a paper by Li, Jiao and Chen on the solubility of SO2 in several solvents, including DEA. The title of the paper is "Solubility of sulphur dioxide in polar organic solvents". Unfortunately, the paper is not complete enough to be useful. It gives solubility at several temperatures, but it does not specify what the partial pressure is for SO2 equilibrated with the liquid. This means that the data in the paper is useless in its present form. I am actually surprised it got past the peer review process.
SO2 (which is a gas) can be bought in cylinders. I believe HBr (which is also a gas) can also be bought in cylinders. In principle it should not be too hard to build an apparatus that would allow SO2 and HBr to be added to DEA. Of course, good safety practices would need to be followed. On approach would be to treat DEA in two separate fractions, one for SO2 and one for HBr and then combine the two solutions in the proper proportions.
This means that it should not take a pressure vessel to dissolve the required amount of SO2 into HC-110. This considerably relaxes the technical requirement to make a safe process for adding SO2 to the mixture.
101 bar (i.e. one atmosphere pressure)
Good point.If you're thinking of doing this, isn't it much easier to simply take out Sulphite from the formula of the concentrate? Sulphite can always be added while preparing the working solution.
And another question: would storing the new style HC-110 in the fridge extend the shelf life? A wild card is whether refrigeration might cause precipitation of some components, but if not then it seems likely that refrigeration might extend the shelf life by several fold.
That is what Sino Promise (the new source of Kodak chemicals) recommends - the HC-110 datasheet linked to on their website is just the old Kodak Alaris datasheet which was the old Eastman Kodak datasheet, except the company names were changed.Thanks, Charles. So I should just ignore the fact that this solution is so much thinner and use it like the old HC-110 syrup? I would feel better if there was some documentation. However, if that is the way you are using the new HC-110 then I will try it using it the same way. So if I have a 16 oz. developing tank then I can just take 1/2 ox of HC-110 from the bottle and mix it with 15 1/2 oz of water. Then I could do away with mixing a "stock" solution. That would be easy.
With respect to the first part of your post, that behavior is actually closer to the manufacturer's recommendations than the old stuff!I’ve found that the new HC-110 formula loses strength when mixed and stored properly in glass bottles over the course of about two months. This might seem long, but compare to the old HC-110, which was stable mixed and stored in same conditions for 6-8 months or more.
I also suspect as the concentrate gets older, this “working time” for mixed developer decreases as well.
Dilution B, and characterizing new emulsion batches for dry plates.
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