Quote Originally Posted by ChristopherCoy View Post
I intend to test it, but do older lenses like this ever have swirling or blurriness on the edges at all?

It's a 90mm so considering that I can even get it mounted on a lens board, I should theoretically have enough room to play if using it for 6x6, right?
Enlarging lenses shouldn't add any blur or swirl.

Older lenses may or may not be corrected for colour.

A 90mm lens will make slightly smaller enlargements than the 80mm lenses which are optimized for 6x6.

On the other hand, a 90mm lens will have a bit more coverage than an 80mm lens, so you will be using more of the lens' "sweet spot" and less of the lens' corners when you are enlarging 6x6.