Re: Is it ok to put oilpaintings under glass?
I mount my oils done on paper to a piece of sealed tempered hardboard, gatorbord or ACM panel, apply a permanent sealing layer such as a very thin layer of Galkyd Lite to help isolate the paper from atmospheric contaminants and moisture. When the sealing coat is touch dry, I mount them in a frame just like you would an oil on panel or canvas. No need for glass. I have done several pieces like this and they hold up very well. The paper is a bit more impact sensitive than canvas, but not much when mounted on an ACM panel with a Galkyd Lite sealing coat. The Galkyd will give a similar slight warming tone like you would see with Damar Varnish, but unlike Damar, it won't get darker over time. Test first before using it on something important.
The key word for the Galkyd sealing layer is PERMANENT. You cannot remove it once it is dry. You can apply a removable conservation varnish as the final coat, in gloss, satin or matte if desired.