I made a painting with acrylic paint (strong type) on paper. I think it's around 150 g/m², so it is not necessary a paper which is impossible to use for acrylic paintings. I'm using it to make quick paintings without investing too much work, but sometimes a good painting might come out which I'd like to preserve.

The paper tends to warp and roll up after drying, but as far as I can see only in one direction, so there are no bumps and humps.

Nevertheless given the case I wanted to preserve one of these trials, I think I want to fix it onto a straight surface like a cardboard or plywood. I could do it temporarily e.g. using tacks or other piercing stuff.

But I'm interested in good ways to fix it permanently to a stiff and straight substrate without piercing the artwork. Hence it boils down to glueing in some way.

What are the best substrates and what type of glue should I use?

I already made some thoughts of it:

Given the properties of the acrylic paint, I think the glue should not ooze through the paper too much, as it may discolor the paint, which is permeable to some degree I think. I think water based glue could work but it may be necessary to press the painting to the substrate for prolonged time.