A while back Ilford introduced a new chart and App for reciprocity failure compensation are you finding he app/chart accurate?

[Vetus]

I've seen that some people use the old times, some use the revised app/chart and a few do their own tests.
What method are you using to determine reciprocity failure with Ilford/Kentmere films?

 

[loccdor]

Erring on the side of more exposure.

This is a 2 minute exposure at f/22 on Ilford HP5+ @ 400. I was ballparking it. But that only translates to EV6 (30 sec -> 90 sec with reciprocity) which is exposing for something lit in average artificial room light. Not appropriate for a darker night scene. You can see that only the areas very close to the lights look well-exposed. The end result is that the important highlights aren't blown, but I wanted more detail in the shadows. It would have been better if I took it at 5-7 minutes or changed to f/16.

All this to say, it's more likely that you'll find the error in the way you're metering the light than in your reciprocity factor. Unless you're going to be extremely meticulous, I think it's easier to just shoot a couple brackets. Once you do a few of those, you'll know what settings will work for just about anything. It's negative film after all.

I have color shots around the same scene on Fuji Pro 400H that are roughly 7 minute exposures at f/22. Those look much better.