Spectral Power Distributions

1

• Spectral Power Distributions
• blackbody Planckian radiators

2

• Plancks Law
• h Plancks constant
• k Boltzman constant
• c speed of light
• ? wavelength
• T absolute temperature

3

• Candle flame (1000K)

4

• 100 W tungsten bulb (2856K)

5

• Photoflood 500 W bulb (3400K)

6

• Sunlight (5500K)

7

• Skylight (12000K)

8

• Absolute vs. relative spectral power

9

• Plancks Law
• h Plancks constant
• k Boltzman constant
• c speed of light
• ? wavelength
• T absolute temperature

10

• Stefan-Boltzman Law
• total power output
• Total power s T 4
• s Stefan-Boltzman constant
• T temperature Kelvins

11

• Weins Displacement Law
• wavelength at peak output
• ?max b/T
• b 2.898 x 10-3 (m K)
• T temperature Kelvins

12
CIE 1988 photopic visibility function V(?)
nm V(?)
nm V(?)
380 0.0002
390 0.0008
400 0.0028
410 0.0074
420 0.0175
430 0.0273
440 0.0379
450 0.0468
460 0.0600
470 0.0910
480 0.1390
490 0.2080
500 0.3230
510 0.5030
520 0.7100
530 0.8620
540 0.9540
550 0.9950
560 0.9950
570 0.9520
580 0.8700
590 0.7570
600 0.6310
610 0.5030
620 0.3810
630 0.2650
640 0.1750
650 0.1070
660 0.0610
670 0.0320
680 0.0170
690 0.0082
700 0.0041
710 0.0021
720 0.0011
730 0.0005
740 0.0002
750 0.0001
760 0.0001
770 0.0000
13
CIE 1988 photopic visibility function V(?) with
2856K 5500K blackbody radiators
5500K
V(?)
2856K
14
CIE 1988 photopic visibility function V(?) with
2856K 5500K blackbody radiators
15
Radiometric constants (ISO units, distance
meters)
Constants Planck's constant h 6.63E-34 J
s speed of light c 3.00E08 m/s Boltzman's
constant k 1.38E-23 J/K Wein's
constant b 2.90E-03 m K Stefan-Boltzman
constant s 5.670E-8 W/m2 K4