colour.colorimetry.blackbody Module¶
Blackbody  Planckian Radiator¶
Defines objects to compute the spectral radiance of a planckian radiator and its spectral power distribution.
See also

colour.colorimetry.blackbody.
planck_law
(wavelength, temperature, c1=3.741771e16, c2=0.014388, n=1)[source]¶ Returns the spectral radiance of a blackbody at thermodynamic temperature \(T[K]\) in a medium having index of refraction \(n\).
Notes
The following form implementation is expressed in term of wavelength. The SI unit of radiance is watts per steradian per square metre.
References
[1] CIE TC 148. (2004). APPENDIX E. INFORMATION ON THE USE OF PLANCK’S EQUATION FOR STANDARD AIR. In CIE 015:2004 Colorimetry, 3rd Edition (pp. 77–82). ISBN:9783901906336 Parameters:  wavelength (numeric or array_like) – Wavelength in meters.
 temperature (numeric or array_like) – Temperature \(T[K]\) in kelvin degrees.
 c1 (numeric or array_like, optional) – The official value of \(c1\) is provided by the Committee on Data for Science and Technology (CODATA), and is \(c1=3,741771x10.16\ W/m_2\) (Mohr and Taylor, 2000).
 c2 (numeric or array_like, optional) – Since \(T\) is measured on the International Temperature Scale, the value of \(c2\) used in colorimetry should follow that adopted in the current International Temperature Scale (ITS90) (PrestonThomas, 1990; Mielenz et aI., 1991), namely \(c2=1,4388x10.2\ m/K\).
 n (numeric or array_like, optional) – Medium index of refraction. For dry air at 15°C and 101 325 Pa, containing 0,03 percent by volume of carbon dioxide, it is approximately 1,00028 throughout the visible region although CIE 15:2004 recommends using \(n=1\).
Returns: Radiance in watts per steradian per square metre.
Return type: numeric or ndarray
Examples
>>> # Doctests ellipsis for Python 2.x compatibility. >>> planck_law(500 * 1e9, 5500) 20472701909806.5...

colour.colorimetry.blackbody.
blackbody_spectral_radiance
(wavelength, temperature, c1=3.741771e16, c2=0.014388, n=1)¶ Returns the spectral radiance of a blackbody at thermodynamic temperature \(T[K]\) in a medium having index of refraction \(n\).
Notes
The following form implementation is expressed in term of wavelength. The SI unit of radiance is watts per steradian per square metre.
References
[1] CIE TC 148. (2004). APPENDIX E. INFORMATION ON THE USE OF PLANCK’S EQUATION FOR STANDARD AIR. In CIE 015:2004 Colorimetry, 3rd Edition (pp. 77–82). ISBN:9783901906336 Parameters:  wavelength (numeric or array_like) – Wavelength in meters.
 temperature (numeric or array_like) – Temperature \(T[K]\) in kelvin degrees.
 c1 (numeric or array_like, optional) – The official value of \(c1\) is provided by the Committee on Data for Science and Technology (CODATA), and is \(c1=3,741771x10.16\ W/m_2\) (Mohr and Taylor, 2000).
 c2 (numeric or array_like, optional) – Since \(T\) is measured on the International Temperature Scale, the value of \(c2\) used in colorimetry should follow that adopted in the current International Temperature Scale (ITS90) (PrestonThomas, 1990; Mielenz et aI., 1991), namely \(c2=1,4388x10.2\ m/K\).
 n (numeric or array_like, optional) – Medium index of refraction. For dry air at 15°C and 101 325 Pa, containing 0,03 percent by volume of carbon dioxide, it is approximately 1,00028 throughout the visible region although CIE 15:2004 recommends using \(n=1\).
Returns: Radiance in watts per steradian per square metre.
Return type: numeric or ndarray
Examples
>>> # Doctests ellipsis for Python 2.x compatibility. >>> planck_law(500 * 1e9, 5500) 20472701909806.5...

colour.colorimetry.blackbody.
blackbody_spd
(temperature, shape=SpectralShape(360.0, 830.0, 1.0), c1=3.741771e16, c2=0.014388, n=1)[source]¶ Returns the spectral power distribution of the planckian radiator for given temperature \(T[K]\).
Parameters:  temperature (numeric) – Temperature \(T[K]\) in kelvin degrees.
 shape (SpectralShape, optional) – Spectral shape used to create the spectral power distribution of the planckian radiator.
 c1 (numeric, optional) – The official value of \(c1\) is provided by the Committee on Data for Science and Technology (CODATA), and is \(c1=3,741771x10.16\ W/m_2\) (Mohr and Taylor, 2000).
 c2 (numeric, optional) – Since \(T\) is measured on the International Temperature Scale, the value of \(c2\) used in colorimetry should follow that adopted in the current International Temperature Scale (ITS90) (PrestonThomas, 1990; Mielenz et aI., 1991), namely \(c2=1,4388x10.2\ m/K\).
 n (numeric, optional) – Medium index of refraction. For dry air at 15°C and 101 325 Pa, containing 0,03 percent by volume of carbon dioxide, it is approximately 1,00028 throughout the visible region although CIE 15:2004 recommends using \(n=1\).
Returns: Blackbody spectral power distribution.
Return type: Examples
>>> from colour import STANDARD_OBSERVERS_CMFS >>> cmfs = STANDARD_OBSERVERS_CMFS.get( ... 'CIE 1931 2 Degree Standard Observer') >>> blackbody_spd(5000, cmfs.shape) <colour.colorimetry.spectrum.SpectralPowerDistribution object at 0x...>