Measured Normal Emissivities (bron  infrared-thermography.com)
Material
Emissivity
Wavelength
Silver plated Cu bus bar.
0.30
3.4-5 mm
Stainless Steel
0.59
3.4-5 mm
Stainless Plate
0.34
3.4-5 mm
Stainless Steel Bolt - Shiny
0.32
3.4-5 mm
UHMW (green plastic)
0.87
3.4-5 mm
Plastic insulation on cables
0.95
3.4-5 mm
Black Iron Pipe
0.95
3.4-5 mm
Tarnished Mild Steel Plate
0.70
3.4-5 mm
Galvanized Pipe
0.46
3.4-5 mm
Spray Bar Flat Black Paint
0.92
3.4-5 mm
Shiny Copper
0.24
3.4-5 mm
Copper - oxidized, slightly dirty
0.50
3.4-5 mm
Copper - Xformer plate, slightly oxidized
0.22
3.4-5 mm
Copper - Xformer plate, failed, pitted from welder
0.32
3.4-5 mm
Copper - New shank
0.20
3.4-5 mm
Copper - Slightly oxidized patina
<0.1
3.4-5 mm
Cu - Heavily oxidized
0.64
3.4-5 mm
Heavily oxidized copper
0.69
3.4-5 mm
Wood - varnished
0.93
3.4-5 mm
White paint
0.77
3.4-5 mm
Al - Slightly oxidized, slightly greasy
0.37
3.4-5 mm
Al - splice
0.23
3.4-5 mm
Al - Weathered and pitted
0.58
3.4-5 mm
Fuse - Shiny end cap, new
0.25
3.4-5 mm
Fuse - Body, new, yellow
0.78
3.4-5 mm
Gypsum Wall Board
0.67
3.4-5 mm