I finished this painting yesterday. It is oil on carefully sanded ABS plastic and measures 8x10”.
I use ABS for all my small works, those measuring 18x24” or less. The white plastic sheet is shiny smooth on one side and has a ripple pattern on the back side. I sand the white shiny side until it is as smooth as a traditional gesso panel and loses the shine. I use a 220 grit sandpaper and a rotary palm sander. I then finish sand it with 400 grit wet-or-dry paper. I do not need to prime it for oil painting. If the painting doesn’t work, I simply sand it off and start over. ABS is very archival.