No fancy pictures because all I used was a step chart and enlarger.. but did test and find out a number of things.
PFS-4 mixed with photographic grade TEA (ie, clear not yellow) is not as potent. Seems to require double the working strength and 25% more time for equivalent results. It does seem somewhat more stable to use with photographic TEA with less fogging, but actually looks to lose ~1/2 stop in unstable speed compared to technical grade TEA. Timing and such could potentially be adjusted further with pH balancing
PFS-4 as a stock solution seems to keep pretty much forever. The batch I mixed in August is still just as good today
PFS-4 can not be replaced by a simple carbonate+bromide solution. It’s clearly the TEA itself that is doing something to the film, not just having a basic environment with bromide present
The “stable” speed increase of Arista Ortho Litho with PFS-4 is ~2 stops. The unstable (ie, can be fogged/show artifacts) speed increase is ~3 stops.
PFS-4 is effective on Kodalith, though to a much lesser extent. The speed of Kodalith with nothing special is about 2.5 stops faster than Arista, and PFS-4 only adds 0.5-1 stop extra, though does seem to degrade the highlights somewhat and thus resulting in a more pleasant tonal scale, rather than going very dark on the negative, they go to a more mild grey. End result is that the speed of Kodalith with PFS-4 roughly matches that of Arista, but with a steeper contrast curve.
PFS-4 does NOT work on Kodak positive microfilm (ie, what FPP sells). Absolutely no difference is made between the two. Also, a fun fact people don’t mention is that it is blue sensitive only and can be processed under red safelight, maybe even amber safelight