Quote Originally Posted by sandermarijn View Post
Are you sure? I'm not a chemist, but many sources say that sodium sulphite does work to help 'clear the hypo'.

See e.g. Ralph Lambrecht's formula for HCA-1 in Way Beyond Monochrome (2nd edition), p. 504: just water and sodium sulphite (and sodium hexametaphosphate if the local water is 'hard').

Perhaps I'm reading you the wrong way and you mean to say that a sodium sulphite solution only works in conjunction with sufficient plain water rinsing?

Sander
The sodium sulphite is not chemically as effective in reacting away the thiosulphate, for that the metabisulphite is needed. My understanding is that the sulphite component in hypoclear is there to prevent unnecessary oxidation of metabisulphite, i.e. to extend the shelf life. I am not saying the sulphite does not work, but it certainly is less effective than a combination of sulphite and metabisulphite. Typically rinsing times are reduced from 30 minutes to 5 for paper, and 15 minutes to 2 for film. I use hypoclear, rinse under the tap briefly, and then do two stand rinses of 2-3 minutes each in clean water, after which I just flush the film under running tap water very briefly again and then do a final dunking in distilled water with a drop or two of wetting agent (Agepon). It takes less than 3 liters of water to process two films, if one works sparingly.