Here is chart from Kodak TRI X 400/320
It looks close to Kodak data (see pdf file below)
In general
FOMAPAN 400 Action is a panchromatically sensitized, black-and-white negative
film designed for taking photographs under unfavourable light conditions or using
short exposure times. The film meets high requirements for low granularity, good
resolving power and good contour sharpness. FOMAPAN 400 Action has a nominal
speed rating of ISO 400/27o, but due to its wide exposure latitude the film gives
good results even when overexposed by 1 EV (exposure value) (as ISO 200/24 o)
or underexposed by 2 EV (as ISO 1600/33o) without any change in processing, i.e.
without lengthening the development time or increasing the temperature of the
developer used.
To make prints or enlargements, Fomabrom- and Fomaspeed-type enlarging
papers are recommended; however, all sorts of black-and-white enlargement
papers can be used.
Speed
ISO 400/27o, 27 o ČSN
Schwarzschild effect
Exposure (seconds) ----------1/1000–1/2 __1__ 10 _100
Lengthening of exposure ------1x ---------1.5x -6x- -8x
Correction of aperture number _0 _________-1__ -2.5 -3
Dave
I've used several hundred sheets of Arista EDU Ultra film 100, 200, and 400 in the 4"x5" and 8"x10" formats. In every case I rate the films at half their nominal speeds and I do tray development in a slosher or one sheet at a time. Replenished Xtol is my developer of choice and development time is 11 minutes 15 seconds for all films at 20 Celcius. All the films are unremarkable, predictable, high quality, panchromatic, and feature conventional silver halide technology. Arista EDU Ultra 400 seems grainier than other 400 speed films but for large format work at the moderate enlargements I do the grain is irrelevant.
Since Arista EDU Ultra 200 is supposed to have the worst reciprocity characteristics of any film I did actual tests to see how bad things really are. Here are my results for a consistent negative density at extended times:
Measure 1 second on the meter...give 1.5 seconds
Measure 2 ... give 4
Measure 3 ... give 7
Measure 4 ... give 12
Measure 6 ... give 18
Measure 8 ... give 28
Measure 10 ... give 40
Measure 14 ... give 48
In practice I deal with dark scenes by reading subject luminances consistent with Zone VII or VIII and apply reciprocity corrections to keep these Zones pegged where they should be. Shadows will of course experience stronger reciprocity failure and become featureless black. But this is how dark scenes should look so I don't worry about letting the shadows go.