One more thing that may or may not be obvious from looking at the exposure curve falling off at the bottom end: this effect means you get increased contrast at exposure levels where reciprocity failure is an issue (anything over about 1s for traditional emulsions like Foma & Efke/Adox produce). That's not necessarily a big problem unless you also push the development and get crazy contrast. To make it worse, the falloff curve is convex, which means that you get greater shadow contrast than highlight contrast.

And Schwarzchild effect is a perfectly good name for it, named after its discoverer, it's just that Americans use the term reciprocity failure; the ignorant ones just calling it "reciprocity" which is about as annoying as referring to hypo clearing agent as "hypo". If you look at the Fomapan datasheet, it gives you the reciprocity failure curve (and its one of the worst films for this) labelled as "Schwarzchild effect".