[numpad0]

There are single solution spray-on electroless plating "paint" for modelmaking. They can make any smooth and black surface into a mirror so I think it's just a matter of surface preparations.

[michaelt]

Can they actually produce a mirror you could mistake for a glass mirror?

I assume if your mirror is "only" as good as as the shiny side of some aluminium foil, you can't project things with any detail.

[numpad0]

Isn't the mirror surface effectively at the aperture in this system...