On 09/08/2012 22:54, Martin Brown wrote:

Basically any shiny metal behaves to some extent as a reflector of IR
wavelengths. Most resin paints and common materials are black in the
thermal IR including glass windows.

Regards,
Martin Brown

I'd love to find a reference for your comments on paints. I have a work
job at the moment where this is a very real issue. IR spectra by ATR
show relatively narrow absorption bands with high transmission in
between. These are paints on blast cleaned (i.e. rough) steel. Are we
getting absorption at the metal-paint interface? Coating thickness is
200 - 250 microns, two pack epoxy and polysiloxane "white" paint.

TIA
Steve