Bob Burridge, Evening Demo at the Casa 2014 

Instablaster.

Hi Shoutyahoo, he seals the paper before painting on it with acrylic gesso so the acrylic paint doesn't get soaked up by the paper, he also uses his gesso as his white paint. He seals the finished work with either an acrylic varnish, or a poly acrylic, (min wax), usually matte. Also, you don't want to use the acrylic medium to varnish with, because by it's nature it dries porous in order to bind with more layers of paint, (and thus dust and grime over time is harder to remove), where as varnish dries in a solid impermeable surface, (but can still bind with more layers of acrylic should you want to add to it at a later date). Making a varnished painting much easier to clean, thus the advantage of varnishing.

thanks for your detailed answer, much appreciated :-)

Casa de los Artistas, ArtWorkshopVacations.com

Hi Ann, he seals the paper before painting on it with acrylic gesso so the acrylic paint doesn't get soaked up by the paper, -use less paint and gives you more "open" "play" time - he also uses his gesso as his white paint. He seals the finished work with either an acrylic varnish, or a poly acrylic, (min wax), usually matte. Also, you don't want to use the acrylic medium to varnish with, because by it's nature it dries porous in order to bind with more layers of paint, (and thus dust and grime over time is harder to remove), where as varnish dries in a solid impermeable surface, (but can still bind with more layers of acrylic should you want to add to it at a later date). Making a varnished painting much easier to clean, thus the advantage of varnishing. Show less