Originally Posted by Photo Engineer
I am sorry but I have to respectfully disagree with you. I understand you background, but having worked in the analytical industry and working with equipment that looked for levels of inorganics(metals including sodium,calcium,etc,etc)down to ppt levels, distillation will not remove all inorganics. Boiling will not remove all insoluble salts etc.
You need to either use reverse osmosis or ion exchange cartridges to remove them.Now I am sure that for the levels photography would be bothered about, distillation would be more then good enough.
In the UK, things like DW are not so easy for 'joe public' to get now. It is thought that you must be making bombs if you want anything 'chemistry like' at all!!
BUT I am not wanting to get into a discussion as which method is better. For photography, I would settle for some DW. In the UK a lot of labs went over to DI rather then DW because of allsorts of problems from owning a still and inspections etc. It was just easier to buy bulk from people like BDH.