Kodak gives very sensible instructions for small tank processing on their web site. It involves intermittent agitation that avoids bubbles in the developer. But, all water has dissolved air in it. And, bubbles arise from water exiting the tap into your sink. Watch for it on film when you wash the film. Tiny bubbles there with no agitation. The idea is to break up those bubbles by using agitation. At least that is one purpose of agitation.
I use the straight syrup out of the bottle. 12 mL in 600 mL water, one-shot developer. Inversion that takes 2 sec. to invert and return to upright. Invert 15 times in the first 30 sec. and 5 inversions in 10 sec. at each minute, on minutes one through eight. Pour out developer at 9 minutes development time for TMY-2. I use Indicator Stop then I use Eco Pro fixer for 7 minutes with the same inversions as developing. Works well for what I want. This is for ISO 400.
I'm certain the fix times recommeded for TF4 are intended to be well beyond merely adequate. I standardize on 5 min for all film types, and have no doubt it is more than ample.
Look at the film as it washes. You will see tiny bubbles on the film caused from air entrained in the wash water. This can cause uneven washing with resulting dots of brown from retained hypo. We called it "measles". So, some sort of agitation should be used even in the wash. I just remove the reel from the tank and tap it a few times, then return it to the wash tank. I do this every time I see the bubbles accumulate.
This is not well known.
There was a huge staff of professional photographers at EK when I was there. They did not do lab experiments, they did the type of work, in the field, that any pro did! We had elaborate studios with sets and props and all of the studio lighting equipment you could imagine, and we had labs for them to process and print int.
So, these methods were tried and perfected by true professionals.
I might add that we had a fairly large staff of "Kodak Girls" (and guys) who were used as models both indoors and out.
Thanks for that explanation, Ron. I didn't read your post carefully enough to realize you were talking about washing. I thought it was about development agitation.
The method I use to wash film is with an upright dedicated film washer, where the reels are stacked on top of each other, just like in a developing tank. Extra air is introduced to the wash water, which causes a type of turbulent water flow. No air bubbles accumulate on the film surface in this washer, but I imagine that with plain running water it might.