Originally Posted by Sarcasm-hime
Gesso is a primer used for preparing artist's canvases before painting. It's white and looks like paint, but has solids in it that can be sanded. You want to apply several layers and sand with fine-grain sandpaper.
For best results, see if you can find "Hard Sandable Gesso" at an art supply store. It has more solids in it than regular gesso (it's thicker) and so you'll get smoother results with less work.
ok so how many layers should i apply before i start sanding it and should i also apply Gesso to the inside of the mask as well?