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Athiril

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    Physics, Chemistry, Optics

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  1. I thought I typed up a reply.. lost it. Anyway, I can use sodium thiocyanate, or even sodium thiosulphate, they at least perform the function of clearing the film density, so the reversal is opposite of the negative, not the negative + a whole lot more density that never got used. In any case, iirc, potassium thiocyanate does give finer grain. Which is why I wanted it, my photo supplier only has sodium thiocyanate, and it's pricey, and I already have that anyway. Well, the problem then is, how do I get to NH4SCN? I can get to a thiocyanate from thiosulphate and a cyanide, so I assume I use potassium ferricyande for the cyanide source. But I am unsure of the reaction, and whether say ammonium thiosulphate will give a mix of ammonium thiocyanate and potassium cyanate or just one or the other?
  2. I thought I typed up a reply.. lost it. Anyway, I can use sodium thiocyanate, or even sodium thiosulphate, they at least perform the function of clearing the film density, so the reversal is opposite of the negative, not the negative + a whole lot more density that never got used. In any case, iirc, potassium thiocyanate does give finer grain. Which is why I wanted it, my photo supplier only has sodium thiocyanate, and it's pricey, and I already have that anyway. Well, the problem then is, how do I get to NH4SCN? I can get to a thiocyanate from thiosulphate and a cyanide, so I assume I use potassium ferricyande for the cyanide source. But I am unsure of the reaction, and whether say ammonium thiosulphate will give a mix of ammonium thiocyanate and potassium cyanate or just one or the other?
  3. Well some research shows caffeine as a carcinogen or potential carcinogen, others say no.
  4. triple post... sorry one click of my mouse often registers as many clicks with no timing between them..
  5. I'm also not a food chemist, but couldn't you test for sugars with sulfuric acid? Also it may be worth hitting up a patent search for all those protein/amino acid supplements - the process they use. Also if you have something like http://www.proteindirect.com.au/?page_id=3 for your country (this stuff here is imported from U.S. iirc.. so you should?) You can get whey protein concentrate and isolate pretty darn cheaply without other crap in it. I don't know if that's helpful but just putting it out there.
  6. Hi all, I already have sodium thiocyanate which I can use for the purposes I want potassium thiocyanate (additive in b&w developer to make b&W or colour positive images in a reversal process on photographic film), but potassium thiocyanate gives finer grain. I was wondering how to get to potassium thiocyanate, online the most I can find is a reaction between a thiosulphate and cyanide. So a thiosulphate and potassium ferricyanide in some kind of function may give me what I need? Is it as simple as a 1:1 molar ratio of thiosulphate to ferricyanide? Do I need the potassium salt to be on the thiosulphate side as well? Or only on the ferricyanide side? As I have ammonium thiosulphate, but adding KOH would give potassium thiosulphate and ammonium hydroxide, correct? Just want some general pointers (a link, or otherwise) on the best approach to potassium thiocyanate and purification. Sorry if I sound stupid, my chemistry knowledge is only practical towards analogue photography, so I pretty much only know most things on a case-by-case basis rather than on general principles.
  7. The other portion of your brain that is "not" being used is being used, it's there for repair and rebuilding pathways, but in a more complex way that I can state to you. Let's say telepathy and other such abilities exist in some people somehow somewhere. I do not think you should be deciding how they function and looking for what could support them based on existing knowledge of completely different functions unrelated to humans.. how do I say it... it's coming up with a conclusion and looking for evidence to support it, rather than gathering evidence and making a conclusion which you continue to update as you can obtain more evidence. I don't think you have any evidence for such a conclusion. I don't believe such abilities cannot and do not exist. I think it's fine to make some research into such fields, but do it with a more sound/solid approach.
  8. How about baking soda/sodium bicarbonate from the supermarket? That is food grade. Also you can bake or heat the powder to form sodium carbonate from that. You can also get food grade sodium hydroxide (not from the supermarket obviously).
  9. Hi, So bubbling chlorine through potassium ferrocyanide is a production method for potassium ferricyanide. I use potassium ferricyanide as a bleach for films with a halide salt. As it gets used, potassium ferrocyanide is formed. So I can regenerate this by bubbling chlorine gas through the solution. If I use Sodium Chloride (normally it's Bromide, but Chloride works fine for bleaching purposes too) I'll have less trouble, and the chlorine will also re-halogenate the solution, although perhaps I should use potassium chloride. In any case, my question is; Once all ferrocyanide has been converted to ferricyanide is there a further reaction? Potassium Ferricyanide produces nasty stuff with strong mineral acids (like HCl), so I would assume after some point HCN gas is produced, is this correct? If so, how do you know when to stop the reaction to avoid this? I want to completely avoid HCN production (Since it's a production method of ferricyanide... where is the stopping point? etc). Or does the fact that chlorine gas only make dilute HCl in this case not affect it? Also if i buffer the solution very well, I can completely avoid it right? (working solution should be pH ~6.5 for best colour balance on film) My solution would be a mix of potassium ferricyanide, potassium ferrocyanide, and a chloride salt. I'd like to do this, as a) It'd be quite simple to do, I've used chlorine gas for several other experiments and am setup to do this. b) It's very cost efficient, and saves me from having to throw out spent bleach solution and keep using more potassium ferricyanide.
  10. Name's Dan and I'm an unwashed home-chemist peasant. Most of my chemical interest usually has some way of tying back to analogue photography. I live in Melbourne, Australia, and have accumulated a nice collection of useful substances
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