I recently got an Industar 61 L/D lens. This 53mm f2.8 Leica Screw mount lens dates from Soviet Russia, I think my copy is 70’s vintage. The L/D designation means that the lens glass contains radioactive Lanthanum!
Voigtlander Bessa R, 53mm/2.8 Industar 61/LD Lens
Tri-X, developed in Pyrocat HD,1+1+100,
15 minutes @ 20 C