Painting on copper

I've been experimenting lately with working on copper, and I love it.  This is today's progress on the current project.  It's 5x5 inches.  The copper surface is prepared (I'll write about that another time), and then primed.  For effect, about a 1/2 inch border of unprimed copper is left to show through; it gives it a fantastic warm and luminous effect.  The composition is then sketched in and as much charcoal as possible is rubbed out (left side).  A color block-in is then painted (right side).  The colors are WAY off in this image (they were taken on my phone, where there's no white balance setting), and needless to say, this is just the first stage of the painting.  After it's dried a few days, I'll begin applying glazes for color depth and enrichment as well as working the details.  More later.