I am planning to display a number of large prints without glazing. If I spray them with Desert Varnish Lacquer, can they subsequently be dry-mounted using heat? Or should they be sprayed later? (In which case, must the wood frame be shielded from the spray?) Thank you.

I would recommend applying the Desert Varnish before mounting. It should be unaffected by the dry mount press, and if you wait until after mounting the wood and/or frame would have to be masked to avoid any discoloration due to the spray.