frogprince - to return to the original question about shiny black cars reflecting your face. The link "ask a scientist" gives an answer, but it is a bit over complicated sounding. A simpler desription would be :-
Paints (and things which act like paints - e.g. boot polish) are usually made from a coloured powder mixed in a "carrier" which is a clear liquid. Some paints dry because the carrier (e.g.water) evaporates, leaving the powder on the surface - this would give a matt finish. Other paints dry because the carrier changes chemically and remains part of the overall finish. In the case of your car paint (or lacquer)the carrier turns into a shiny clear coating with the paint powder embedded in it. The colour particles are surrounded by the clear finish.
The first thing light hits is the clear shiny finish, which acts like a sheet of glass would, reflecting your face. Any light that passes beyond the surface will then reach the embedded coloured "paint" particles.
If these are white, they will reflect light back through the outer glossy surface. The light you see will be the initial "mirror" reflection plus all the "white" reflected by the paint particles. RESULT - most of what you see is WHITE.
If the particles are black, light absorbing "paint" most of the light will be absorbed, so very little is reflected back at you. What you see is the "mirror" reflection, without extra reflected light behind it.

Hope that helps.
Quack!
Geoff.