As different films experience reciprocity failure in different ways, you may want to clarify that your question applies to long exposures (if it does) so those who use the film in those conditions can help you.
And Fomapan 100/Arista EDU 100 has *absurdly* terrible reciprocity failure, making it probably a poor choice for pinhole work unless you have bright conditions and/or a long time to wait around for an exposure. I've actually used it quite a bit for long nighttime exposures, developed in Diafine---15 minutes at f/8 was my typical starting point for your average nighttime cityscape, and if you scale that time to pinhole apertures...
San Diego, CA, USA
The lady of the house has to be a pretty swell sort of person to put up with the annoyance of a photographer.
-The Little Technical Library, _Developing, Printing, And Enlarging_