GG

Picked up a 8x10 Burke and James a little while back. The GG looks like it wearing off, I thought GG was just that ground into the glass. Anybody care to tell me how older GG were made?

The glass is ground with a fine wet paste to mark the surface. The are a few articles on here where people have done it.

The glass is ground but the grid pattern appears to be a coating which look like its wearing off, especially in the middle off the GG