How to treat impression fossils.... would this be okay?

Question

We found some fossils that are impressions on river rocks.

My idea is to use playdough to fill in the impression and then spray clear enamel over the rock, then remove the playdough to leave the unfinished impression in the rock, making it pop.

Answer 1

I have done it. One trick as I was told by an old expert is to fill it with  clay(playdough) or a mixture of water and corn starch that is allowed to dry then spray two very thin coats.

Remove the clay.

Replace the clay and respray two thin coats.

Then remove the clay for the final time.

This will prevent edge chips or crackling.

Make sure that if its like a black rock and use glossy,

Whiter rocks use a glossy/ Matte Finnish mix of coats-