Technical Support

Emissivity in the Infrared


Emissivity Table

Emissivity is a measure of a material’s radiating efficiency.  An emissivity of 1.00 implies that the material is 100% efficient at radiating energy.  An emissivity of 0.20 implies that the material radiates only 20% of that which it is capable of radiating.

Tables of emissivity values are only approximated values for real materials.  A range of emissivity values is usually given for many materials whose emissivity can be affected by surface roughness or finish.  Additionally, thin sheets of material such as plastics may be semi-transparent in the infrared and therefore have reduced emissivity.

To optimize the surface temperature measurement of a material:

 

Note: Applicable for material temperatures from 0 to 250°C

Alumel 
Unoxidized0.10 - 0.25
Oxidized0.60
Oxidized0.60
  
Aluminum 
Polished0.10 - 0.05
Oxidized0.10 - 0.40
Rough0.10 - 0.30
Anodized0.60 - 0.95
  
Aluminum Oxide0.40
Asbestos0.95
Asphalt0.90 - 1.00
Basalt0.70
Bismuth0.50
  
Brass 
Polished0.05
Oxidized0.50 - 0.60
Burnished0.30
  
Carbon 
Unoxidized0.40 - 0.90
Filament0.50
Soot0.50 - 0.95
Coke0.95 - 1.00
Graphite0.70 - 0.80
  
Carborundum0.80 - 0.90
Ceramic0.90 - 0.95
  
Clay 
Fired0.95
  
Concrete0.95
  
Chromel 
Oxidized0.60 - 0.85
  
Chromium0.10
Cobalt0.20
  
Columbium 
Polished0.20
Oxidized0.70
  
Copper 
Polished0.10
Oxidized0.20 - 0.80
  
Electrical terminal blocks0.60
Enamel0.90
Foods0.85 - 1.00
Formica0.95
Mullite0.80 - 0.85
  
Glass 
Convex D0.80
Nonex0.80
Plate0.90 - 0.95
Fused quartz0.75
Pyrex, lead and soda0.95
  
Gold0.05
  
Granite 
Polished0.85
Rough0.90
Natural0.95
  
Gravel0.90 - 0.95
Gypsum0.85 - 0.95
Haynes Alloy0.30 - 0.80
Human Skin0.99
  
Inconel 
Polished0.15
Oxidized0.70 - 0.95
Sandblasted0.30 - 0.66
  
Iron 
Polished0.20
Oxidized0.50 - 0.95
Rusted0.50 - 0.70
Wrought, dull0.90
  
Iron Oxide0.85
  
Lacquer 
Colored on Al0.75 - 0.90
Colored0.95
Clear on Al0.10
Clear on Cu0.65
  
Lead 
Polished0.05 - 0.10
Oxidized0.30 - 0.65
Rough0.40
  
Limestone0.95 - 1.00
Magnesium Oxide0.55
  
Molybdenum 
Polished0.05
Oxidized0.20 - 0.80
  
Monel 
Oxidized0.45 - 0.85
  
Nichrome 
Clean0.65
Oxidized0.60 - 0.85
  
Nickel 
Polished0.10
Oxidized0.20 - 0.95
  
Nickel Oxide0.60
  
Oil 
Animal/vegetable0.95 - 1.00
Mineral0.90 - 1.00
0.001” thick0.25
0.002” thick0.46
0.005” thick0.70
  
Paint 
Aluminum paint0.50
Bronze paint0.80
Paint on metal0.60 - 0.90
Paint on plastic or wood0.80 - 0.95
Gold enamel0.40
Clear silicone0.65 - 0.80
  
Paper0.85 - 1.00
Plaster0.90
Plastic0.95 - 1.00
Platinum0.05
Polyester0.75 - 0.85
Polyethylene0.10
Quartz0.90
Roofing Paper0.90
  
Rubber 
Hard glossy0.95
Soft rough0.85
  
Sand0.80 - 0.90
Sandstone0.70
Shale0.70
  
Silica 
Powder0.35 - 0.60
Glazed0.85
Unglazed0.75
  
Silicone Carbide0.80 - 0.95
Silver0.05
  
Soil 
Dry0.90 - 0.95
Wet0.95 - 1.00
  
Slate0.70 - 0.80
  
Stainless Steel 
Polished0.10 - 0.15
Oxidized0.45 - 0.95
  
Steel 
Unoxidized0.10
Oxidized0.70 - 0.95
Cold Rolled0.70 - 0.90
Ground sheet0.40 - 0.60
Rough surface0.95
  
Tantalum 
Unoxidized0.20
Oxidized0.60
  
Textiles 
Carpet0.85 - 1.00
Close weave0.70 - 0.95
Cotton0.80
Leather0.95 - 1.00
Silk0.80
Died black0.98
  
Tin 
Unoxidized0.05 - 0.10
  
Tungsten 
Unoxidized0.05
Filament0.30
  
Water 
Liquid0.90 - 0.95
Ice0.95 - 1.00
Snow0.80 - 1.00
  
Wood 
Planed0.80 - 0.95
Sawdust0.75
  
Zinc 
Polished0.05
Oxidized0.10
Galvanized0.20 - 0.30