Roger, it is TF-4 and TF-5. The information for each is a pdf file under tech info.

See here:

Tom, since Kodak no longer makes B&W paper, their instructions are moot in the sense that they have no modern papers and no R&D unit to run tests. However, their tests do hold up. Hypo never reaches zero. Haist shows that both Hypo and Hydroquinone are retained and contribute to keeping problems and thus must be removed to an archival level. Mason gives the math behind this process. You can never reach zero though. But you can overwash, especailly RC paper. See the article by Ctein.