Bullseye fiber paper causing opaque glass to be Matt

[helenrudy]

I am making some pieces where the base glass is opaque bullseye color, red, blue etc. and it is fired directly onto the fiber paper On the shelf. The opaque glass where it is fired onto the paper is losing its sheen and is Matt and almost has a dusty appearance. Does anyone know why.
Any thoughts on what is causing this and how to prevent it.
Helen

[Brock]

Prevent it by using kiln wash. Cheaper and effective.

[helenrudy]

I have been lazy with the paper. I hate it when the opaque glass sometimes stick to shelf and leaves a dent.

[Jeanne]

Are you venting the kiln to 1000 degrees?

[Laurie Spray]

How hot are you firing?

[Valerie Adams]

Are you expecting your base sheet of opal glass to remain glossy on the bottom? That's not going to happen whether you use shelf paper or shelf wash. The bottom of your piece, during a full-fuse process, will pick up the texture of whatever you're firing it on.