I DIY mix most of my colour film developers. Thre are excellent formulae out there, as well as some more than suspect. One of the C-41 constituents ingredients is a dye neutralizer, as I understand it, called hydroxylamine sulfate. I refered to it as HAS. I know it is not the nicest compound in the world, and treat it with respect, wrt storage, ventilation while mixing and the use of appropriate PPE use when handling HAS. My stock of HAS is getting low, and my old domestic supplier of the stuff, JD Photochem is no longer trading. The Formulary makes it but is not allowed to export it outside of the USA. I can totally understand why. This stuff has other than colour photographic possibilities to be a precursor for all sorts of nefarious agents. I have inherited a defunct biochem blood products research lab stock of chemistry. Part of these stocks includes a modest 25 or so grams of hydroxylamine hydrochloride. It too, I know, needs to be handled with respect. It is deliquescent, but I suspect my HAS is also, to some degree. My HAS's texture has changed in the plastic bag inside the plastic jar I store it in over rthe 5 years that I have had it. I am trying to figure ot what the opportunities there may be to make an equimolar substitiution on the hydroxylamine component out of the (NH3OH) HCl alternate instead of the (NH3OH)2SO4 normal component. I am not an organic, or inorganic chemist (electrical engineer, actually). I suspect that the HAS in solution breaks down to its ionic constituents. The NH3OH, which is the oxidizer, consumes the surplus dye stuffs. The Sulfate ions, well apart from perhaps gobbling any available H ions to influnce the pH of the solution, I am not sure what they do to the other silver reduction-dye forming reactions. If my thoery of ionic action holds as perhaps being correct, then my initial thinking is if I use an equimolar NH3OH component, it will merrily go on it's way as though it came from a sulfate salt solution. The way the HCL will react is the biggest unknown. I suspect it may act as a restrainter, weaker in action than the nominated restrainers, potassium bromide and iodide, but enough that the molar conribution of the bromides and iodides may need to be adjusted. I know that the pH will have to be adjusted more to bring the pH in line with the target level if I make the substitution. Can other more knowing souls passs comments on on this idea? Alternately could they at least point me to chemical tomes that will perhaps set right my confused half knoweldge of the fuctioning of the chemistry that I have set out here?