| Name | Start | End | Notes |
|---|---|---|---|
| Ultra Violet | 0.01 um | 0.4 um | 0.39 um bandwidth. Um = microns = micro metres = millionths of a metre |
| Violet | 0.4 um | 0.45 um | 0.05 um bandwidth. Visible Light |
| Blue | 0.45 um | 0.5 um/td> | 0.05 um bandwidth. Visible Light |
| Green | 0.5 um | 0.75 um | 0.25 um bandwidth. Visible Light |
| Yellow | 0.57 um | 0.59 um | 0.02um bandwidth. Visible Light |
| Orange | 0.59 um | 0.61 um | 0.02 um bandwidth. Visible Light |
| Red | 0.61 um | 0.7 um | 0.09 um bandwidth Visible Light |
| Near Infrared | 0.7 um | 1.0 um* | 0.3 um* bandwidth. Optical infrared electronics. E.g. remote controls, IRDA, Light beam safety barriers etc. |
| Medium Infrared | 1.0 um* | 10 um* | 9 um* bandwidth. Radiated heat, Passive infrared detectors (PIR) etc. |
| Far Infrared | 10 um* | 1000 um | 990 um* bandwidth. To be determined |
*Note these values are guidelines only, actual values are to be confirmed
The graph shows a plot for each of the set absolute temperatures (Kelvin). Each plot gives the wavelength against radiance.
Kelvin is absolute temperature; it uses the same scale as centigrade. To convert between centigrade and Kelvin just add or subtract 273 as required.
For example;
0° Centigrade + 273 = 273°K
The Human Body core temperature is 37°C adding 273 gives us 310°K.
From Figure 2 - Black Body Spectral Radiance we can estimate a plot for 310°K which would lie roughly in the middle of the 273 and 400 plots. This will give us peak radiance in the wavelength range of 6 um to 10 um which lies in the medium infrared range.
The NASA web site http://science.hq.nasa.gov/kids/imagers/ems/infrared.html suggests the human body at normal temperature will radiate most strongly at a wavelength of about 10 microns (um). This aligns reasonably well with the black body graph above.
(Updated: 20th June 2008)