A comment, and a question for David at Ilford. First, ditto on the two-bath fixing method either with standard or rapid fixers. Note that the capacities recommended by Ilford (and I presume Kodak as well) change with designated end use of prints. I quote their fact sheet "Processing B&W Paper": "A silver level of 2g/l is safe for all commercial use with fibre base papers. This approximates to 40 20.3x25.4cm (8x10 inches) prints per litre of working strength fixer (one bath method!). For prints with maximum stability, that is, for long term storage, a silver level of 0.5g/l should be used (approximately 10 20.3x25.4cm (8x10 inches) prints." The two-bath fixing method extends this capacity. Again I quote: "The capacity of a fixer can be significantly increased, while still obtaining optimum permanence, by using a second fixing bath. When the silver level of the first bath has reached 2g/l (approximately 40 20.3x25 . 4cm prints per litre of working strength fixer), discard it and replace it with the second bath. Make up a fresh second bath. This cycle can be repeated up to four times but, in any case, replace both baths after one week." For further info, download the PDF version of the above document from the Ilford web site.(posted 8418 days ago)Now my query for David: I have recently been using Ilford Hypam mixed 1:9 for film (not paper) and using it one-shot. My guide for fixing times is to fix for three times the clearing time which is determined by a clip-test. The times are longer, but the negatives processed in this manner pass my residual hypo and residual silver tests. In this way I can avoid mixing and storing working strength film fixer and just mix the amount I need to fix the batch of film I'm developing at the moment. Also, since I use pyro, this cuts down on fixer loss due to developer contamination. The capacities are arrived at by using the Ilford recommendations with a generous "fudge factor". Is there any disadvantage at all to this method as concerns film longevity, complete fixing and washing (my test seem to indicate not)? And why is this practice not mentioned or recommended since it is more economical, more environmentally sound, and, for us small batch processors, eliminates the need to store partially used fixer for the next batch? Any ideas/responses would be welcome, particularly from the Ilford tech department.
Regards, ;^D)