Re: gum exposures with NuArc 26-1K?
PS: I once had a student sho discovered after long trail of tears that her easel had been equipped with UV proof glass by a well-meaning glazier. She was having new glass put in prepratory to teaching her first workshop after graduating. Class was a shambles, as you can perhaps imagine, until somehow she stumbled on the cause.
That UV glass is of course intended for picture framing, to keep prints from fading on s sunny wall..