Quote Originally Posted by E. von Hoegh View Post
Your Walz filter is probably a gel sandwiched between two pieces of glass. It's deteriorating; get a good filter say a Kodak or other. Quite a lot of accesories were made for these cameras, a little digging should turn something up.
I have decided not to use it, the crackling in it turned out to be microscopic hairline cracks on both sides of the glass. I believe you may be correct about it being a gel sandwiched between two glass pieces.

I will see if I can find a 30mm Series V Drop-In filter of the same type and use an adapter.

Now I just have to find some of these filters in very good to excellent condition.