Quote Originally Posted by PHOTOTONE View Post
Sorry, I must be missing something here, but isn't Efke IR820 in metal 35mm cassettes just like all other 35mm films? If so, doesn't the metal cassette provide enough protection for loading under subdued light? Is there "light-piping" from the leader into the film inside? What does Efke say about loading?

The reason IR film manufacturers recommend loading in darkness is the film lacks an anti-halation layer. This means that if the leader is exposed to light while loading the light can 'hosepipe' along the roll (think fibre optics and you get the idea) and fog the first few frames (or even the whole roll if the light is strong enough).
Obviously this is not an issue with 120 as there is no film leader.