I was curious as to how much sanding is usually necessary before priming.

Is it normal to sand old or even relatively new paint completely off before priming, or just enough so that the primer adheres?

I ask because I'm restoring some old artwork on a plywood cabinet, and if I don't sand it off completely it would be easier to restore the art by masking and going over it with each of the three or four colors originally used rather than to have to start from scratch.

The artwork was originally done in lacquer paint, however the paint I'm using to restore it is latex.

Thanks.

Darren Harris
Staten Island, New York.