Description Usage Arguments Details Value References See Also

Two families of standard illuminants that depend on temperature are the Planckian spectra (black-body spectra), and daylight spectra. For the daylight spectra, a smoothed version is available. Illuminant E, a third and trivial spectrum, is also available.

1 2 3 4 5 6 | ```
planckSpectra( temperature, wavelength=300:830, normalize=TRUE, c2=1.4388e7 )
daylightSpectra( temperature, wavelength=NULL,
components=colorSpec::daylight1964, roundMs=FALSE )
illuminantE( energy=1, wavelength=380:780 )
``` |

`temperature` |
a vector of temperatures, in Kelvin |

`wavelength` |
a vector of wavelengths.
For |

`normalize` |
a logical value.
If |

`c2` |
the value of |

`components` |
a |

`roundMs` |
a logical value. The original CIE method for the daylight spectra requires
rounding intermediate coefficients M1 and M2 to 3 decimal places.
This rounding is necessary to reproduce the tabulated values in Table T.1 of the CIE
publication in |

`energy` |
a vector of energy levels |

For `daylightSpectra()`

the valid range of temperatures is 4000 to 25000 K.
For a temperature outside this range the spectrum is set to all `NA`

s.

The equations for `daylightSpectra()`

and `planckSpectra()`

are complex
and can be found in the **References**.

`IlluminantE()`

is trivial - all constant energy.

For `planckSpectra()`

and `daylightSpectra()`

:

A **colorSpec** object with `quantity`

equal to `'energy'`

,
and `organization`

equal to `'matrix'`

or `'vector'`

.
The `specname`

s are `PNNNN`

or `DNNNN`

for `planckSpectra()`

and `daylightSpectra()`

respectively.

The number of spectra in the object is the number of temperatures = `length(temperature)`

.

For `illuminantE()`

:

A **colorSpec** object with `quantity`

equal to `'energy'`

.

The number of spectra in the object is the number of energy levels = `length(energy)`

.

Günther Wyszecki and W.S. Stiles.
**Color Science : Concepts and Methods, Quantitative Data and Formulae**.
Second Edition.
Wiley-Interscience. 1982.
page 146.

CIE 15: Technical Report: Colorimetry, 3rd edition. CIE 15:2004. Table T.1, pp 30-32, and Note 5 on page 69.

Schanda, Janos.
CIE Colorimetry, in
*Colorimetry: Understanding the CIE System*.
Wiley Interscience. 2007.
p. 42.

daylight, `resample`

, `organization`

, `quantity`

,
materialSpectra

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