Hi Sandy:
No one has responded to this yet and I don't know the complete answer, but I thought I would share what I do know about it.
There are several different ways you can mount artwork. You can easily take it to a framing shop and have them dry mount it for you. It will cost you some, but it is probably the most permanent and professional way to do it.
Also, if you want to do it yourself, then there are what I believe are called PVA backing which are sheets that peel off from two sides. They are acid free and should be available from any moulding supply store.
For a spray option, there is a spray mount that is also acid free out there that you could use.
Finally, there are mounting corners - little stick on pieces of plastic that the corners of the work slip into. I would want some additional holding mechanism in addition to the corners.
Hope that helps.
Hybrid Mode
