Haze, any remedy?

[Brian Bullen]

I have a Cooke Series IIA "Pressic" 6 1/4" with a fair amount of haze on the rear element. I'm wondering what causes haze on a lens, also is there any remedy for this type of problem?

[Kevin Crisp]

Haze on glass on the outside is probably very fine scratches. It needs to be polished off. Focal Point does that well. Haze internally could be something on an air to glass surface which is cleaned following disassembly. This could be caused by outgassing of paint or cement, air pollution or smoking, among other things. If the element is cemented (I don't know the construction of the lens) and the haze is inside you need to decement it and reglue it. Sometimes the cement does start to deteriorate and it looks like internal haze.