If you've been to any contemporary art shows recently, you've likely seen a painting or five with a very thick, very glossy layer on top of the color. It's most likely a layer of epoxy resin, which is great for short-term gloss but have longevity issues in terms of yellowing and cracking because it's so rigid. So would a self-leveling acrylic medium work as a replacement? Here's an expert's answer...
Introduction to Acrylic Paint Mediums
Pouring Acrylic Instead of Brushing