The process, worked out over a few cold nights in the yard. Laser-etch the pattern into the mirror’s protective backing, then lay the glass flat and pour on a mix of hydrogen peroxide, salt and white vinegar. The solution eats through the exposed silver and copper and stops where the backing protects it, so the image comes up out of the mirror in reverse.
It has to be done outside, the fumes are not something you want in a room. A photograph of one lying on a pallet at night, the portrait surfacing as the metal lifts.
Part of the Mirrors (Open House) case study.