I’ve started to paint on birch plywood panels, the plywood is low formaldehyde Baltic birch. I’ve treated the panels with ph neutral archival PVA (4 coats) and then acrylic gesso (front and back). I’ve built a frame to hold wet paintings that will hold 2 sizes of panel. It’s a really nice panel to work with. Once paintings are dry, I’ll brace them with 14mm plywood (also low formaldehyde Baltic birch).