As you may have noticed, the reciprocity failure compensation graphs in Ilford's film literature are generic. A few years ago I had a discussion with Harman tech service about how frankly lousy Ilford's and Kodak's low intensity reciprocity failure (LIRF) compensation charts were/are. After some back and forth they decided to carry out new, film-specific LIRF testing. I followed along as Harman went through this process and the revised factors have now been publicly released. Notice most of the factors are substantially different than the old chart indicated.

https://www.ilfordphoto.com/wp/wp-co...mpensation.pdf