Bill, it does seem like rinse duration is an issue in your case, and I'd agree with Michael, that your fixing time seems to be on a longer side, which would require a longer rinse. I do not know the Kodak Rapid Fix formulation, but I believe it has to be quite acidic, if it allows the use of a hardener. Too much acid in the print will cause staining in KRST. If your holding bath has many prints and not much turnover, plus a longish fixing time, you are bound to have this issue, as you are adding more and more acid into it with each print. Some of the people who I know and trust who use Kodak fixers, use 2-bath fixing, with the second bath quite neutral, made of plain sodium thiosulfate (but it does not keep). Prints remain in a holding bath after the first (acidic) fix, but they go straight from the second fix into KRST with no intermediate rinse.
If you would like to shorten the rinses and your overall process time, so that prints have been toned and are dry the next morning, consider a less acidic fixer.
For what it is worth, I use Ilford Rapid Fixer, which is only mildly acidic, hence it cannot be used with a hardener. Sometimes, I use Ryuji's fully neutral rapid fix, but the process is the same as with Ilford Rapid. I use it as per Ilford recommendation, 1+4 (film strength, ie. ca 10-12% ammonium thiosulfate) for about 1 min, single bath, then a quick rinse of 10-20 mins, and then into KRST 1+9. No staining using MGWT or MGIV fibre. Then wash aid (HCA, or 2% sodium sulfite) for 3-4 minutes, then a running rinse of 45-60 min in a slot washer. My prints test excellent for residual thiosulfate and residual silver halide.
By the way, an overconcentrated stop bath can also lead to staining in the Se toner. However, I wonder if yours is too weak, perhaps: I thought the Kodak Indicator Stop was supposed to be diluted 1+63. For 32 fl oz, ca. 1000cc, you would need about 15cc of it, not the 4cc you have mentioned. Considering that you only use 1 l of the stop, assuming a typical print size (8x10 or 11x14), and maybe 10-20 sheets of it in a session, this would mean that you might have another issue of an unneutralised developer carrying over from stop into the fix, causing another unwanted interaction. Having said that, your description (brown or yellow cream colour stain) fits the overly acidic print hypothesis better than this alternative, which could lead to dichroic fog stain.
PS. I was just refreshing my memory from Tim Rudman's "Toning Book". He mentions selenium staining a good few times, notably on p 46. To sum up, it is either underfixing or acid in the print. In addition to what has already been mentioned, he suggests using a bath of a wash aid (HCA etc) prior to toning, as a way to neutralise the acid from the fixer. As an aside, he also mentions that, apparently, this was one of the reasons Ansel Adams recommended diluting KRST with working strength HCA, instead of water, to help prevent staining.
If you would like to shorten the rinses and your overall process time, so that prints have been toned and are dry the next morning, consider a less acidic fixer.
For what it is worth, I use Ilford Rapid Fixer, which is only mildly acidic, hence it cannot be used with a hardener. Sometimes, I use Ryuji's fully neutral rapid fix, but the process is the same as with Ilford Rapid. I use it as per Ilford recommendation, 1+4 (film strength, ie. ca 10-12% ammonium thiosulfate) for about 1 min, single bath, then a quick rinse of 10-20 mins, and then into KRST 1+9. No staining using MGWT or MGIV fibre. Then wash aid (HCA, or 2% sodium sulfite) for 3-4 minutes, then a running rinse of 45-60 min in a slot washer. My prints test excellent for residual thiosulfate and residual silver halide.
By the way, an overconcentrated stop bath can also lead to staining in the Se toner. However, I wonder if yours is too weak, perhaps: I thought the Kodak Indicator Stop was supposed to be diluted 1+63. For 32 fl oz, ca. 1000cc, you would need about 15cc of it, not the 4cc you have mentioned. Considering that you only use 1 l of the stop, assuming a typical print size (8x10 or 11x14), and maybe 10-20 sheets of it in a session, this would mean that you might have another issue of an unneutralised developer carrying over from stop into the fix, causing another unwanted interaction. Having said that, your description (brown or yellow cream colour stain) fits the overly acidic print hypothesis better than this alternative, which could lead to dichroic fog stain.
PS. I was just refreshing my memory from Tim Rudman's "Toning Book". He mentions selenium staining a good few times, notably on p 46. To sum up, it is either underfixing or acid in the print. In addition to what has already been mentioned, he suggests using a bath of a wash aid (HCA etc) prior to toning, as a way to neutralise the acid from the fixer. As an aside, he also mentions that, apparently, this was one of the reasons Ansel Adams recommended diluting KRST with working strength HCA, instead of water, to help prevent staining.
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