Clark Solutions

Infrared Thermometers

Technical bulletin: Emissivity

Understanding an object's emissivity, or its characteristic "radiance" is a critical component in the proper handling of infrared measurements. Concisely, emissivity is the ratio of radiation emitted by a surface or blackbody and its theoretical radiation predicted from Planck's law [W(L,T)=C1/(L^5*(exp(C2/LT)-1)].

A material's surface emissivity is measured by the amount of energy emitted when the surface is directly observed. There are many variables that affect a specific object's emissivity, such as the wavelength of interest, field of view, the geometric shape of the blackbody, and temperature. However, for the purposes and applications of the infrared thermometer user, a comprehensive table showing the emissivity at corresponding temperatures of various surfaces and objects is displayed.

Material (Non-Metals)		Temp °F (°C)	Emissivity
Adobe		68 (20)	0.9
Asbestos
	Board	100 (38)	0.96
	Cement	32-392 (0-200)	0.96
	Cement, Red	2500 (1371)	0.67
	Cement, White	2500 (1371)	0.65
	Cloth	199 (93)	0.9
	Paper	100-700 (38-371)	0.93
	Slate	68 (20)	0.97
	Asphalt, pavement	100 (38)	0.93
	Asphalt, tar paper	68 (20)	0.93
Basalt		68 (20)	0.72
Brick
	Red, rough	70 (21)	0.93
	Gault Cream	2500-5000 (1371-2760)	.26-.30
	Fire Clay	2500 (1371)	0.75
	Light Buff	1000 (538)	0.8
	Lime Clay	2500 (1371)	0.43
	Fire Brick	1832 (1000)	.75-.80
	Magnesite, Refractory	1832 (1000)	0.38
	Grey Brick	2012 (1100)	0.75
	Silica, Glazed	2000 (1093)	0.88
	Silica, Unglazed	2000 (1093)	0.8
	Sandlime	2500-5000 (1371-2760)	.59-.63
Carborundum		1850 (1010)	0.92
Ceramic
	Alumina on Inconel	800-2000 (427-1093)	.69-.45
	Earthenware, Glazed	70 (21)	0.9
	Earthenware, Matte	70 (21)	0.93
	Greens No. 5210-2C	200-750 (93-399)	.89-.82
	Coating No. C20A	200-750 (93-399)	.73-.67
	Porcelain	72 (22)	0.92
	White Al2O3	200 (93)	0.9
	Zirconia on Inconel	800-2000 (427-1093)	.62-.45
Clay		68 (20)	0.39
	Fired	158 (70)	0.91
	Shale	68 (20)	0.69
	Tiles, Light Red	2500-5000 (1371-2760)	.32-.34
	Tiles, Red	2500-5000 (1371-2760)	.40-.51
	Tiles, Dark Purple	2500-5000 (1371- 2760)	0.78
Concrete
	Rough	32-2000 (0-1093)	0.94
	Tiles, Natural	2500-5000 (1371-2760)	.63-.62
	Brown	2500-5000 (1371-2760)	.87-.83
	Black	2500-5000 (1371-2760)	.94-.91
Cotton Cloth		68 (20)	0.77
Dolomite Lime		68 (20)	0.41
Emery Corundum		176 (80)	0.86
Glass
	Convex D	212 (100)	0.8
	Convex D	600 (316)	0.8
	Convex D	932 (500)	0.76
	Nonex	212 (100)	0.82
	Nonex	600 (316)	0.82
	Nonex	932 (500)	0.78
	Smooth	32-200 (0-93)	.92-.94
Granite		70 (21)	0.45
Gravel		100 (38)	0.28
Gypsum		68 (20)	.80-.90
Ice, Smooth		32 (0)	0.97
Ice, Rough		32 (0)	0.98
Lacquer
	Black	200 (93)	0.96
	Blue, on Al Foil	100 (38)	0.78
	Clear, on Al Foil (2 coats)	200 (93)	.08-.09
	Clear, on Bright Cu	200 (93)	0.66
	Clear, on Tarnished Cu	200 (93)	0.64
	Red, on Al Foil (2 coats)	100 (38)	.60-.74
	White	200 (93)	0.95
	White, on Al Foil (2 coats)	100 (38)	.69-.88
	Yellow , on Al Foil (2 coats)	100 (38)	.57-.79
Lime Mortar		100-500 (38-260)	.90-.92
Limestone		100 (38)	0.95
Marble, White		100 (38)	0.95
	Smooth, White	100 (38)	0.56
	Polished Grey	100 (38)	0.75
Mica		100 (38)	0.75
Oil on Nickel
	0.001 Film	72 (22)	0.27
	0.002 Film	72 (22)	0.46
	0.005 Film	72 (22)	0.72
	Thick Film	72 (22)	0.82
Oil, Linseed
	On Al Foil, uncoated	250 (121)	0.09
	On Al Foil, 1 coat	250 (121)	0.56
	On Al Foil, 2 coats	250 (121)	0.51
	On Polished Iron, .001 Film	100 (38)	0.22
	On Polished Iron, .002 Film	100 (38)	0.45
	On Polished Iron, .004 Film	100 (38)	0.65
	On Polished Iron, Thick Film	100 (38)	0.83
Paints
	Blue, Cu2O3	75 (24)	0.94
	Black, CuO	75 (24)	0.96
	Green, Cu2O3	75 (24)	0.92
	Red, Fe2O3	75 (24)	0.91
	White, Al2O3	75 (24)	0.94
	White, Y2O3	75 (24)	0.9
	White, ZnO	75 (24)	0.95
	White, MgCO3	75 (24)	0.91
	White, ZrO2	75 (24)	0.95
	White, ThO2	75 (24)	0.9
	White, MgO	75 (24)	0.91
	White, PbCO3	75 (24)	0.93
	Yellow , PbO	75 (24)	0.9
	Yellow , PbCrO4	75 (24)	0.93
Paints, Aluminum		100 (38)	.27-.67
	10% Al	100 (38)	0.52
	26% Al	100 (38)	0.3
	Dow XP-310	200 (93)	0.22
Paints, Bronze		Low	.34-.80
	Gum Varnish (2 coats)	70 (21)	0.53
	Gum Varnish (3 coats)	70 (21)	0.5
	Cellulose Binder (2 coats)	70 (21)	0.34
Paints, Oil
	All colors	200 (93)	.92-.96
	Black	200 (93)	0.92
	Black Gloss	70 (21)	0.9
	Camouflage Green	125 (52)	0.85
	Flat Black	80 (27)	0.88
	Flat White	80 (27)	0.91
	Grey-Green	70 (21)	0.95
	Green	200 (93)	0.95
	Lamp Black	209 (98)	0.96
	Red	200 (93)	0.95
	White	200 (93)	0.94
Quartz, Rough, Fused		70 (21)	0.93
	Glass, 1.98 mm	540 (282)	0.9
	Glass, 1.98 mm	1540 (838)	0.41
	Glass, 6.88 mm	540 (282)	0.93
	Glass, 6.88 mm	1540 (838)	0.47
	Opaque	570 (299)	0.92
	Opaque	1540 (838)	0.68
Red Lead		212 (100)	0.93
Rubber, Hard		74 (23)	0.94
Rubber, Soft, Grey		76 (24)	0.86
Sand		68 (20)	0.76
Sandstone		100 (38)	0.67
Sandstone, Red		100 (38)	.60-.83
Sawdust		68 (20)	0.75
Shale		68 (20)	0.69
Silica, Glazed		1832 (1000)	0.85
Silica, Unglazed		2012 (1100)	0.75
Silicon Carbide		300-1200 (149-649)	.83-.96
Silk Cloth		68 (20)	0.78
Slate		100 (38)	.67-.80
Snow, Fine Particles		20 (-7)	0.82
Snow, Granular		18 (-8)	0.89
Soil
	Surface	100 (38)	0.38
	Black Loam	68 (20)	0.66
	Plowed Field	68 (20)	0.38
Soot
	Acetylene	75 (24)	0.97
	Camphor	75 (24)	0.94
	Candle	250 (121)	0.95
	Coal	68 (20)	0.95
Stonework		100 (38)	0.93
Water		100 (38)	0.67
Waterglass		68 (20)	0.96
Wood		Low	.80-.90
	Beech, Planed	158 (70)	0.94
	Oak, Planed	100 (38)	0.91
	Spruce, Sanded	100 (38)	0.89

Material (Non-Metals)		Temp °F (°C)	Emissivity
Alloys
	0-Ni, 24-CR, 55-FE, Ox	392 (200)	0.9
	0-Ni, 24-CR, 55-FE, Ox	932(500)	0.97
	0-Ni, 12-CR, 28-FE, Ox	518 (270)	0.89
	0-Ni, 12-CR, 28-FE, Ox	1040 (560)	0.82
	80-Ni, 20-CR, Oxidized	212 (100)	0.87
	80-Ni, 20-CR, Oxidized	1112 (600)	0.87
	80-Ni, 20-CR, Oxidized	2372 (1300)	0.89
Aluminum
	Unoxidized	77 (25)	0.02
	Unoxidized	212 (100)	0.03
	Unoxidized	932 (500)	0.06
	Oxidized	390 (199)	0.11
	Oxidized	1110 (599)	0.19
	Oxidized at 599°C (1110°F)	390 (199)	0.11
	Oxidized at 599°C (1110°F)	1110 (599)	0.19
	Heavily Oxidized	200 (93)	0.2
	Heavily Oxidized	940 (504)	0.31
	Highly Polished	212 (100)	0.09
	Roughly Polished	212 (100)	0.18
	Commercial Sheet	212 (100)	0.09
	Highly Polished Plate	440 (227)	0.04
	Highly Polished Plate	1070 (577)	0.06
	Bright Rolled Plate	338 (170)	0.04
	Bright Rolled Plate	932 (500)	0.05
	Alloy A3003, Oxidized	600 (316)	0.4
	Alloy A3003, Oxidized	900 (482)	0.4
	Alloy 1100-0	200-800 (93-427)	0.05
	Alloy 24ST	75 (24)	0.09
	Alloy 24ST, Polished	75 (24)	0.09
	Alloy 75ST	75 (24)	0.11
	Alloy 75ST, Polished	75 (24)	0.08
Bismuth, Bright		176 (80)	0.34
Bismuth, Unoxidized		77 (25)	0.05
Bismuth, Unoxidized		212 (100)	0.06
Brass
	73% Cu, 27% Zn, Polished	476 (247)	0.03
	73% Cu, 27% Zn, Polished	674 (357)	0.03
	62% Cu, 37% Zn, Polished	494 (257)	0.03
	62% Cu, 37% Zn, Polished	710 (377)	0.04
	83% Cu, 17% Zn, Polished	530 (277)	0.03
	Matte	68 (20)	0.07
	Burnished to Brown Color	68 (20)	0.4
	Cu-Zn, Brass Oxidized	392 (200)	0.61
	Cu-Zn, Brass Oxidized	752 (400)	0.6
	Cu-Zn, Brass Oxidized	1112 (600)	0.61
	Unoxidized	77 (25)	0.04
	Unoxidized	212 (100)	0.04
	Cadmium	77 (25)	0.02
Carbon
	Lampblack	77 (25)	0.95
	Unoxidized	77 (25)	0.81
	Unoxidized	212 (100)	0.81
	Unoxidized	932 (500)	0.79
	Candle Soot	250 (121)	0.95
	Filament	500 (260)	0.95
	Graphitized	212 (100)	0.76
	Graphitized	572 (300)	0.75
	Graphitized	932 (500)	0.71
Chromium		100 (38)	0.08
Chromium		1000 (538)	0.26
Chromium, Polished		302 (150)	0.06
Cobalt, Unoxidized		932 (500)	0.13
Cobalt, Unoxidized		1832 (1000)	0.23
Columbium, Unoxidized		1500 (816)	0.19
Columbium, Unoxidized		2000 (1093)	0.24
Copper
	Cuprous Oxide	100 (38)	0.87
	Cuprous Oxide	500 (260)	0.83
	Cuprous Oxide	1000 (538)	0.77
	Black, Oxidized	100 (38)	0.78
	Etched	100 (38)	0.09
	Matte	100 (38)	0.22
	Roughly Polished	100 (38)	0.07
	Polished	100 (38)	0.03
	Highly Polished	100 (38)	0.02
	Rolled	100 (38)	0.64
	Rough	100 (38)	0.74
	Molten	1000 (538)	0.15
	Molten	1970 (1077)	0.16
	Molten	2230 (1221)	0.13
	Nickel Plated	100-500 (38-260)	0.37
Dow Metal		0.4-600 (-18-316)	0.15
Gold
	Enamel	212 (100)	0.37
	Plate (.0001)	212 (100)	0.37
	Plate on .0005 Silver	200-750 (93-399)	.11-.14
	Plate on .0005 Nickel	200-750 (93-399)	.07-.09
	Polished	100-500 (38-260)	0.02
	Polished	1000-2000 (538-1093)	0.03
Haynes Alloy C
	Oxidized	600-2000 (316-1093)	.90-.96
Haynes Alloy 25
	Oxidized	600-2000 (316-1093)	.86-.89
Haynes Alloy X
	Oxidized	600-2000 (316-1093)	.85-.88
Inconel Sheet		1000 (538)	0.28
Inconel Sheet		1200 (649)	0.42
Inconel Sheet		1400 (760)	0.58
Inconel X, Polished		75 (24)	0.19
Inconel B, Polished		75 (24)	0.21
Iron
	Oxidized	212 (100)	0.74
	Oxidized	930 (499)	0.84
	Oxidized	2190 (1199)	0.89
	Unoxidized	212 (100)	0.05
	Red Rust	77 (25)	0.7
	Rusted	77 (25)	0.65
	Liquid	2760-3220 (1516-1771)	.42-.45
Cast Iron
	Oxidized	390 (199)	0.64
	Oxidized	1110 (599)	0.78
	Unoxidized	212 (100)	0.21
	Strong Oxidation	40 (104)	0.95
	Strong Oxidation	482 (250)	0.95
	Liquid	2795 (1535)	0.29
Wrought Iron
	Dull	77 (25)	0.94
	Dull	660 (349)	0.94
	Smooth	100 (38)	0.35
	Polished	100 (38)	0.28
Lead
	Polished	100-500 (38-260)	.06-.08
	Rough	100 (38)	0.43
	Oxidized	100 (38)	0.43
	Oxidized at 1100	100 (38)	0.63
	Gray Oxidized	100 (38)	0.28
Magnesium		100-500 (38-260)	.07-.13
Magnesium Oxide		1880-3140 (1027-1727)	.16-.20
Mercury		32 (0)	0.09
Mercury		77 (25)	0.1
Mercury		100 (38)	0.1
Mercury		212 (100)	0.12
Molybdenum		100 (38)	0.06
Molybdenum		500 (260)	0.08
Molybdenum		1000 (538)	0.11
Molybdenum		2000 (1093)	0.18
Molybdenum Oxidized at 1000°F		600 (316)	0.8
Molybdenum Oxidized at 1000°F		700 (371)	0.84
Molybdenum Oxidized at 1000°F		800 (427)	0.84
Molybdenum Oxidized at 1000°F		900 (482)	0.83
Molybdenum Oxidized at 1000°F		1000 (538)	0.82
Monel, Ni-Cu		392 (200)	0.41
Monel, Ni-Cu		752 (400)	0.44
Monel, Ni-Cu		1112 (600)	0.46
Monel, Ni-Cu Oxidized		68 (20)	0.43
Monel, Ni-Cu Oxidized at 1110°F		1110 (599)	0.46
Nickel
	Polished	100 (38)	0.05
	Oxidized	100-500 (38-260)	.31-.46
	Unoxidized	77 (25)	0.05
	Unoxidized	212 (100)	0.06
	Unoxidized	932 (500)	0.12
	Unoxidized	1832 (1000)	0.19
	Electrolytic	100 (38)	0.04
	Electrolytic	500 (260)	0.06
	Electrolytic	1000 (538)	0.1
	Electrolytic	2000 (1093)	0.16
Nickel Oxide		1000-2000 (538-1093)	.59-.86
Palladium Plate (.00005 on .0005 silver)		200-750 (93-399)	.16-.17
Platinum		100 (38)	0.05
Platinum		500 (260)	0.05
Platinum		1000 (538)	0.1
Platinum, Black		100 (38)	0.93
Platinum, Black		500 (260)	0.96
Platinum, Black		2000 (1093)	0.97
Platinum Oxidized at 1100		500 (260)	0.07
Platinum Oxidized at 1100		1000 (538)	0.11
Rhodium Flash (0.0002 on 0.0005 Ni)		200-700 (93-371)	.10-.18
Silver
	Plate (0.0005 on Ni)	200-700 (93-371)	.06-.07
	Polished	100 (38)	0.01
	Polished	500 (260)	0.02
	Polished	1000 (538)	0.03
	Polished	2000 (1093)	0.03
Steel
	Cold Rolled	200 (93)	.75-.85
	Ground Sheet	1720-2010 (938-1099)	.55-.61
	Polished Sheet	100 (38)	0.07
	Polished Sheet	500 (260)	0.1
	Polished Sheet	1000 (538)	0.14
	Mild Steel, Polished	75 (24)	0.1
	Mild Steel, Smooth	75 (24)	0.12
	Mild Steel, Liquid	2910-3270 (1599-1793)	0.28
	Steel, Unoxidized	212 (100)	0.08
	Steel, Oxidized	77 (25)	0.8
Steel Alloys
	Type 301, Polished	75 (24)	0.27
	Type 301, Polished	450 (232)	0.57
	Type 301, Polished	1740 (949)	0.55
	Type 303, Oxidized	600-2000 (316-1093)	.74-.87
	Type 310, Rolled	1500-2100 (816-1149)	.56-.81
	Type 316, Polished	75 (24)	0.28
	Type 316, Polished	450 (232)	0.57
	Type 316, Polished	1740 (949)	0.66
	Type 321	200-800 (93-427)	.27-.32
	Type 321 Polished	300-1500 (149-815) .	18-.49
	Type 321 w/BK Oxide	200-800 (93-427)	.66-.76
	Type 347, Oxidized	600-2000 (316-1093)	.87-.91
	Type 350	200-800 (93-427)	.18-.27
	Type 350, Polished	300-1800 (149-982)	.11-.35
	Type 446, Polished	300-1500 (149-815)	.15-.37
	Type 17-7 PH	200-600 (93-316)	.44-.51
	Type 17-7 PH Polished	300-1500 (149-815)	.09-.16
	Type C1020,Oxidized	600-2000 (316-1093)	.87-.91
	Type PH-15-7 MO	300-1200 (149-649)	.07-.19
Stellite, Polished		68 (20)	0.18
Tantalum, Unoxidized		1340 (727)	0.14
Tantalum, Unoxidized		2000 (1093)	0.19
Tantalum, Unoxidized		3600 (1982)	0.26
Tantalum, Unoxidized		5306 (2930)	0.3
Tin, Unoxidized		77 (25)	0.04
Tin, Unoxidized		212 (100)	0.05
Tinned Iron, Bright		76 (24)	0.05
Tinned Iron, Bright		212 (100)	0.08
Titanium
	Alloy C110M,Polished	300-1200 (149-649)	.08-.19
	Oxidized at 538°C (1000°F)	200-800 (93-427)	.51-.61
	Alloy Ti-95A,Oxidized at 538°C (1000°F)	200-800 (93-427)	.35-.48
	Anodized onto SS	200-600 (93-316)	.96-.82
Tungsten
	Unoxidized	77 (25)	0.02
	Unoxidized	212 (100)	0.03
	Unoxidized	932 (500)	0.07
	Unoxidized	1832 (1000)	0.15
	Unoxidized	2732 (1500)	0.23
	Unoxidized	3632 (2000)	0.28
	Filament (Aged)	100 (38)	0.03
	Filament (Aged)	1000 (538)	0.11
	Filament (Aged)	5000 (2760)	0.35
Uranium Oxide		1880 (1027)	0.79
Zinc
	Bright, Galvanized	100 (38)	0.23
	Commercial 99.1%	500 (260)	0.05
	Galvanized	100 (38)	0.28
	Oxidized	500-1000 (260-538)	0.11
	Polished	100 (38)	0.02
	Polished	500 (260)	0.03
	Polished	1000 (538)	0.04
	Polished	2000 (1093)	0.06