My question may seem a little odd but does it always have to be a wood panel for surface?
If I am painting on a plein air panel, isn't it better to
paste my canvas on to a hard plastic examination board with glue? I can make the plastic sheet a
little rough by sanding the surface, cut to fit the size. They are
cheap, lightweight but I don't think they are going to warp. Only thing
to worry about is that if they are hard enough. Is this a good idea?