Colour is a Python colour science package implementing a comprehensive number of colour theory transformations and algorithms.

Highlights:

• RGB and XYZ colour matching functions spectral data:

• Wright & Guild 1931 2 Degree RGB CMFs RGB colour matching functions.
• Stiles & Burch 1955 2 Degree RGB CMFs RGB colour matching functions.
• Stiles & Burch 1959 10 Degree RGB CMFs RGB colour matching functions.
• CIE 1931 2 Degree Standard Observer XYZ colour matching functions.
• CIE 1964 10 Degree Standard Observer XYZ colour matching functions.
• CIE 2012 2 Degree Standard Observer XYZ colour matching functions.
• CIE 2012 10 Degree Standard Observer XYZ colour matching functions.

• Cone fundamentals spectral data:

• Stockman & Sharpe 2 Degree Cone Fundamentals.
• Stockman & Sharpe 10 Degree Cone Fundamentals.

• Photopic & Scotopic luminous efficiency functions spectral data:

• CIE 1924 Photopic Standard Observer
• Judd Modified CIE 1951 Photopic Standard Observer
• Judd-Vos Modified CIE 1978 Photopic Standard Observer
• CIE 1964 Photopic 10 Degree Standard Observer
• CIE 2008 2 Degree Physiologically Relevant LEF
• CIE 2008 10 Degree Physiologically Relevant LEF
• CIE 1951 Scotopic Standard Observer

• Illuminants spectral data:

• A
• B
• C
• D50
• D55
• D60
• D65
• D75
• E
• F1
• F2
• F3
• F4
• F5
• F6
• F7
• F8
• F9
• F10
• F11
• F12
• FL3.1
• FL3.2
• FL3.3
• FL3.4
• FL3.5
• FL3.6
• FL3.7
• FL3.8
• FL3.9
• FL3.10
• FL3.11
• FL3.12
• FL3.13
• FL3.14
• FL3.15
• HP1
• HP2
• HP3
• HP4
• HP5

• Colour rendition charts spectral data.
• Colour appearance models:

• CIECAM02

• Correlated colour temperature calculation:

• Roberston method implementation.
• Yoshi Ohno method implementation.
• McCamy method implementation.
• Hernandez-Andres, Lee & Romero method implementation.
• Kang, Moon, Hong, Lee, Cho and Kim implementation.
• CIE Illuminant D Series implementation.

• Colour matching functions conversions for educational purpose:

• Wright & Guild 1931 2 Degree RGB CMFs to CIE 1931 2 Degree Standard Observer
• Stiles & Burch 1959 10 Degree RGB CMFs to CIE 1964 10 Degree Standard Observer
• Stiles & Burch 1959 10 Degree RGB CMFs to Stockman & Sharpe 10 Degree Cone Fundamentals
• Stockman & Sharpe 2 Degree Cone Fundamentals to CIE 2012 2 Degree Standard Observer
• Stockman & Sharpe 10 Degree Cone Fundamentals to CIE 2012 10 Degree Standard Observer

• Spectral power distribution data manipulation and conversion to tristimulus values.
• Blackbody spectral radiance calculation.
• Spectral bandpass correction.
• Sprague interpolation.
• Chromatic adaptation with following methods:

• XYZ Scaling.
• Bradford.
• Von Kries.
• CAT02.

• Luminance, Munsell value and Lightness calculations:

• Luminance Newhall 1943
• Luminance 1976
• Luminance ASTM D1535-08
• Munsell Value Priest 1920
• Munsell Value Munsell 1933
• Munsell Value Moon 1943
• Munsell Value Saunderson 1944
• Munsell Value Ladd 1955
• Munsell Value McCamy 1987
• Munsell Value ASTM D1535-08
• Lightness Glasser 1958
• Lightness Wyszecki 1964
• Lightness 1976

• RGB Colourspaces support:

• ACES RGB
• ACES RGB Log
• ACES RGB Proxy 10
• ACES RGB Proxy 12
• Adobe RGB 1998
• Adobe Wide Gamut RGB
• ALEXA Wide Gamut RGB
• Apple RGB
• Best RGB
• Beta RGB
• CIE RGB
• ColorMatch RGB
• DCI-P3
• Don RGB 4
• ECI RGB v2
• Ekta Space PS 5
• Max RGB
• NTSC RGB
• Pal/Secam RGB
• ProPhoto RGB
• Rec. 709
• Rec. 2020
• Russell RGB
• S-Log
• SMPTE-C RGB
• Xtreme RGB
• sRGB

• Colourspaces transformations:

• Wavelength to XYZ.
• Spectral to XYZ.
• XYZ to xyY.
• xyY to XYZ.
• xy to XYZ.
• XYZ to xy.
• XYZ to RGB.
• RGB to XYZ.
• xyY to RGB.
• RGB to xyY.
• RGB to RGB.
• XYZ to UCS.
• UCS to XYZ.
• UCS to uv.
• UCS uv to xy.
• XYZ to UVW.
• XYZ to Luv.
• Luv to XYZ.
• Luv to uv.
• Luv uv to xy.
• Luv to LCHuv.
• LCHuv to Luv.
• XYZ to Lab.
• Lab to XYZ.
• Lab to LCHab.
• LCHab to Lab.
• uv to CCT, Duv.
• CCT, Duv to uv.
• xyY to Munsell Colour.
• Munsell Colour to xyY.

Convenience deprecated colourspaces transformations:

• RGB to HSV.
• HSV to RGB.
• RGB to HSL.
• HSL to RGB.
• RGB to CMY.
• CMY to RGB.
• CMY to CMYK.
• CMYK to CMY.
• RGB to HEX.
• HEX to RGB.

• Illuminants chromaticity coordinates data.
• Colourspaces derivation.
• Colour difference calculation with following methods:

• ΔE CIE 1976.
• ΔE CIE 1994.
• ΔE CIE 2000.
• ΔE CMC.

• Colour rendering index calculation.
• Colour rendition chart data.
• RGB colourspaces visualisation within Autodesk Maya.
• First order colour fit.
• Comprehensive plotting capabilities.

The following dependencies are needed:

• Python 2.6.7 or Python 2.7.3: http://www.python.org/

To install Colour from the Python Package Index you can issue this command in a shell:

pip install colour-science

or this alternative command:

easy_install colour-science

You can also install directly from Github source repository:

git clone git://github.com/colour-science/colour.git
cd colour
python setup.py install

• Yoshi Ohno for helping me pinpointing the root cause of calculation discrepancies in my implementation of his CCT & Duv calculation method.
• Charles Poynton for replying to my questions.
• Michael Parsons for all the continuous technical advices.

• Wyszecki & Stiles, Color Science - Concepts and Methods Data and Formulae - Second Edition, Wiley Classics Library Edition, published 2000, ISBN-10: 0-471-39918-3
• Mark D. Fairchild, Color Appearance Models, 2nd Edition, The Wiley-IS&T Series in Imaging Science and Technology, published 19 November 2004, ISBN-13: 978-0470012161
• Stephen Westland, Caterina Ripamonti, Vien Cheung, Computational Colour Science Using MATLAB, 2nd Edition, The Wiley-IS&T Series in Imaging Science and Technology, published July 2012, ISBN-13: 978-0-470-66569-5
• Richard Sewall Hunter, The Measurement of Appearance, 2nd Edition, published August 25, 1987, ISBN-13: 978-0471830061
• Edward J. Giorgianni & Thomas E. Madden, Digital Colour Management: Encoding Solutions - Second Edition, Wiley, published November 2008, ISBN-13: 978-0-470-99436-8
• Charles Poynton, Digital Video and HD: Algorithms and Interfaces, The Morgan Kaufmann Series in Computer Graphics, published December 2, 2012, ISBN-13: 978-0123919267
• Charles Poynton, Color FAQ
• Charles Poynton, Gamma FAQ

• CIE 167:2005 Recommended Practice for Tabulating Spectral Data for Use in Colour Computations: 9.2.4 Method of interpolation for uniformly spaced independent variable (Last accessed 28 May 2014), Stephen Westland, Caterina Ripamonti, Vien Cheung, Computational Colour Science Using MATLAB, 2nd Edition, The Wiley-IS&T Series in Imaging Science and Technology, published July 2012, ISBN-13: 978-0-470-66569-5, Page 33.

• CIE 015:2004 Colorimetry, 3rd edition: Appendix E. Information on the Use of Planck's Equation for Standard Air.

• Bruce Lindbloom, XYZ Scaling Chromatic Adaptation Transform (Last accessed 24 February 2014)
• Bruce Lindbloom, Bradford Chromatic Adaptation Transform (Last accessed 24 February 2014)
• Bruce Lindbloom, Von Kries Chromatic Adaptation Transform (Last accessed 24 February 2014)
• Mark D. Fairchild, Fairchild Chromatic Adaptation Transform (Last accessed 28 July 2014)
• CAT02 Chromatic Adaptation (Last accessed 24 February 2014)

• CIECAM02, Mark D. Fairchild, Color Appearance Models, 2nd Edition, The Wiley-IS&T Series in Imaging Science and Technology, published 19 November 2004, ISBN-13: 978-0470012161, Pages 265-277., CIECAM02, Stephen Westland, Caterina Ripamonti, Vien Cheung, Computational Colour Science Using MATLAB, 2nd Edition, The Wiley-IS&T Series in Imaging Science and Technology, published July 2012, ISBN-13: 978-0-470-66569-5, Pages 88-92., The CIECAM02 Color Appearance Model (Last accessed 30 July 2014)

• Yoshi Ohno, Colour Rendering Index (Last accessed 10 June 2014)

• BabelColor ColorChecker RGB & Spectral Data (Last accessed 24 February 2014)
• N. Ohta, Macbeth ColorChecker Spectral Data (Last accessed 9 June 2014)

• RP 177-1993 SMPTE RECOMMENDED PRACTICE - Television Color Equations: 3.3.2 - 3.3.6 (Last accessed 24 February 2014)

• Bruce Lindbloom, ΔE CIE 1976 (Last accessed 24 February 2014)
• Bruce Lindbloom, ΔE CIE 1994 (Last accessed 24 February 2014)
• Bruce Lindbloom, ΔE CIE 2000 (Last accessed 24 February 2014)
• Bruce Lindbloom, ΔE CMC (Last accessed 24 February 2014)

• Wright & Guild 1931 2 Degree RGB CMFs (Last accessed 12 June 2014)
• Stiles & Burch 1955 2 Degree RGB CMFs (Last accessed 24 February 2014)
• Stiles & Burch 1959 10 Degree RGB CMFs (Last accessed 24 February 2014)
• CIE 1931 2 Degree Standard Observer (Last accessed 24 February 2014)
• CIE 1964 10 Degree Standard Observer (Last accessed 24 February 2014)
• CIE 2012 2 Degree Standard Observer (Last accessed 24 February 2014)
• CIE 2012 10 Degree Standard Observer (Last accessed 24 February 2014)
• Wright & Guild 1931 2 Degree RGB CMFs to CIE 1931 2 Degree Standard Observer, Wyszecki & Stiles, Color Science - Concepts and Methods Data and Formulae - Second Edition, Wiley Classics Library Edition, published 2000, ISBN-10: 0-471-39918-3, Pages 138, 139.
• Stiles & Burch 1959 10 Degree RGB CMFs to CIE 1964 10 Degree Standard Observer, Wyszecki & Stiles, Color Science - Concepts and Methods Data and Formulae - Second Edition, Wiley Classics Library Edition, published 2000, ISBN-10: 0-471-39918-3, Page 141.
• Stiles & Burch 1959 10 Degree RGB CMFs to Stockman & Sharpe 10 Degree Cone Fundamentals (Last accessed 23 June 2014)
• Stockman & Sharpe 2 Degree Cone Fundamentals to CIE 2012 2 Degree Standard Observer (Last accessed 25 June 2014)
• Stockman & Sharpe 10 Degree Cone Fundamentals to CIE 2012 10 Degree Standard Observer (Last accessed 25 June 2014)

• Stockman & Sharpe 2 Degree Cone Fundamentals (Last accessed 23 June 2014)
• Stockman & Sharpe 10 Degree Cone Fundamentals (Last accessed 23 June 2014)

• Alan R. Roberston, Adobe DNG SDK 1.3.0.0: dng_sdk_1_3/dng_sdk/source/dng_temperature.cpp (Last accessed 2 December 2013), Wyszecki & Stiles, Color Science - Concepts and Methods Data and Formulae - Second Edition, Wiley Classics Library Edition, published 2000, ISBN-10: 0-471-39918-3, Page 227
• Yoshi Ohno, Practical Use and Calculation of CCT and Duv (Last accessed 3 March 2014)
• C. S. McCamy, Correlated Colour Temperature Approximation (Last accessed 28 June 2014)
• Javier Hernandez-Andres, Raymond L. Lee, Jr., and Javier Romero, Calculating correlated color temperatures across the entire gamut of daylight and skylight chromaticities (Last accessed 28 June 2014)
• Bongsoon Kang Ohak Moon, Changhee Hong, Honam Lee, Bonghwan Cho and Youngsun Kim, Design of Advanced Color - Temperature Control System for HDTV Applications (Last accessed 29 June 2014)
• CIE Method of Calculating D-Illuminants, D. B. Judd, D. L. Macadam, G. Wyszecki, H. W. Budde, H. R. Condit, S. T. Henderson and J. L. Simonds, Wyszecki & Stiles, Color Science - Concepts and Methods Data and Formulae - Second Edition, Wiley Classics Library Edition, published 2000, ISBN-10: 0-471-39918-3, Page 145

• RGB to HSV (Last accessed 18 May 2014)
• HSV to RGB (Last accessed 18 May 2014)
• RGB to HSL (Last accessed 18 May 2014)
• HSL to RGB (Last accessed 18 May 2014)
• RGB to CMY (Last accessed 18 May 2014)
• CMY to RGB (Last accessed 18 May 2014)
• CMY to CMYK (Last accessed 18 May 2014)
• CMYK to CMY (Last accessed 18 May 2014)

• A (Last accessed 24 February 2014)
• B (Last accessed 12 June 2014)
• C (Last accessed 24 February 2014)
• D50 (Last accessed 24 February 2014)
• D55 (Last accessed 24 February 2014)
• Bruce Lindbloom, D60 (Last accessed 5 April 2014)
• D65 (Last accessed 24 February 2014)
• D75 (Last accessed 24 February 2014)
• F1 (Last accessed 24 February 2014)
• F2 (Last accessed 24 February 2014)
• F3 (Last accessed 24 February 2014)
• F4 (Last accessed 24 February 2014)
• F5 (Last accessed 24 February 2014)
• F6 (Last accessed 24 February 2014)
• F7 (Last accessed 24 February 2014)
• F8 (Last accessed 24 February 2014)
• F9 (Last accessed 24 February 2014)
• F10 (Last accessed 24 February 2014)
• F11 (Last accessed 24 February 2014)
• F12 (Last accessed 24 February 2014)
• FL3.1 (Last accessed 12 June 2014)
• FL3.2 (Last accessed 12 June 2014)
• FL3.3 (Last accessed 12 June 2014)
• FL3.4 (Last accessed 12 June 2014)
• FL3.5 (Last accessed 12 June 2014)
• FL3.6 (Last accessed 12 June 2014)
• FL3.7 (Last accessed 12 June 2014)
• FL3.8 (Last accessed 12 June 2014)
• FL3.9 (Last accessed 12 June 2014)
• FL3.10 (Last accessed 12 June 2014)
• FL3.11 (Last accessed 12 June 2014)
• FL3.12 (Last accessed 12 June 2014)
• FL3.13 (Last accessed 12 June 2014)
• FL3.14 (Last accessed 12 June 2014)
• FL3.15 (Last accessed 12 June 2014)
• HP1 (Last accessed 12 June 2014)
• HP2 (Last accessed 12 June 2014)
• HP3 (Last accessed 12 June 2014)
• HP4 (Last accessed 12 June 2014)
• HP5 (Last accessed 12 June 2014)

• Illuminants Chromaticity Coordinates (Last accessed 24 February 2014)

• Lightness Glasser 1958 (Last accessed 13 April 2014)
• Lightness Wyszecki 1964 (Last accessed 13 April 2014)
• Charles Poynton, Lightness 1976 (Last accessed 12 April 2014)

• Luminance (Last accessed 24 February 2014)
• Luminance Newhall 1943 (Last accessed 13 April 2014)
• Luminance 1976 (Last accessed 12 April 2014)
• Luminance ASTM D1535-08

• CIE 1924 Photopic Standard Observer (Last accessed 19 April 2014)
• Judd Modified CIE 1951 Photopic Standard Observer (Last accessed 19 April 2014)
• Judd-Vos Modified CIE 1978 Photopic Standard Observer (Last accessed 19 April 2014)
• CIE 1964 Photopic 10 Degree Standard Observer (Last accessed 24 February 2014)
• CIE 2008 2 Degree Physiologically Relevant LEF (Last accessed 19 April 2014)
• CIE 2008 10 Degree Physiologically Relevant LEF (Last accessed 19 April 2014)
• CIE 1951 Scotopic Standard Observer (Last accessed 19 April 2014)
• Mesopic Weighting Function (Last accessed 20 June 2014)

• Paul Centore, An Open-Source Inversion Algorithm for the Munsell Renotation (Last accessed 26 July 2014)
• The Munsell and Kubelka-Munk Toolbox (Last accessed 26 July 2014)

• Munsell Value Priest 1920 (Last accessed 13 April 2014)
• Munsell Value Munsell 1933 (Last accessed 13 April 2014)
• Munsell Value Moon 1943 (Last accessed 13 April 2014)
• Munsell Value Saunderson 1944 (Last accessed 13 April 2014)
• Munsell Value Ladd 1955 (Last accessed 13 April 2014)
• Munsell Value ASTM D1535-08 (Last accessed 13 April 2014)
• Munsell Value McCamy 1987, Standard Test Method for Specifying Color by the Munsell System - ASTM-D1535-1989 (Last accessed 23 July 2014)

• A, Wyszecki & Stiles, Color Science - Concepts and Methods Data and Formulae - Second Edition, Wiley Classics Library Edition, published 2000, ISBN-10: 0-471-39918-3, Pages 776, 777
• C, David MacAdam. Maximum Visual Efficiency of Colored Materials JOSA, Vol. 25, Pages 361, 367
• D65, Wyszecki & Stiles, Color Science - Concepts and Methods Data and Formulae - Second Edition, Wiley Classics Library Edition, published 2000, ISBN-10: 0-471-39918-3, Pages 778, 779

• ACES RGB (Last accessed 24 February 2014)
• ACES RGB Log (Last accessed 17 May 2014)
• ACES RGB Proxy 10 (Last accessed 17 May 2014)
• ACES RGB Proxy 12 (Last accessed 17 May 2014)
• Adobe RGB 1998 (Last accessed 24 February 2014)
• Adobe Wide Gamut RGB (Last accessed 13 April 2014)
• ALEXA Wide Gamut RGB (Last accessed 13 April 2014)
• Apple RGB (Last accessed 11 April 2014)
• Best RGB (Last accessed 11 April 2014)
• Beta RGB (Last accessed 11 April 2014)
• CIE RGB (Last accessed 24 February 2014)
• C-Log (Last accessed 18 April 2014)
• ColorMatch Colorspace (Last accessed 12 April 2014)
• DCI-P3 (Last accessed 24 February 2014)
• Don RGB 4 (Last accessed 12 April 2014)
• ECI RGB v2 (Last accessed 13 April 2014)
• Ekta Space PS 5 (Last accessed 13 April 2014)
• Max RGB (Last accessed 12 April 2014)
• NTSC RGB (Last accessed 13 April 2014)
• Pal/Secam RGB (Last accessed 13 April 2014)
• Pointer's Gamut (Last accessed 24 February 2014)
• ProPhoto RGB (Last accessed 24 February 2014)
• Rec. 709 (Last accessed 24 February 2014)
• Rec. 2020 (Last accessed 13 April 2014)
• Russell RGB (Last accessed 11 April 2014)
• S-Log (Last accessed 13 April 2014)
• SMPTE-C RGB (Last accessed 13 April 2014)
• sRGB (Last accessed 24 February 2014)
• Xtreme RGB (Last accessed 12 April 2014)

• Spectral to XYZ Tristimulus Values, Wyszecki & Stiles, Color Science - Concepts and Methods Data and Formulae - Second Edition, Wiley Classics Library Edition, published 2000, ISBN-10: 0-471-39918-3, Page 158.
• Stearns Spectral Bandpass Dependence Correction, Stephen Westland, Caterina Ripamonti, Vien Cheung, Computational Colour Science Using MATLAB, 2nd Edition, The Wiley-IS&T Series in Imaging Science and Technology, published July 2012, ISBN-13: 978-0-470-66569-5, Page 38.
• CIE 167:2005 Recommended Practice for Tabulating Spectral Data for Use in Colour Computations: 9. INTERPOLATION (Last accessed 28 May 2014)
• CIE 015:2004 Colorimetry, 3rd edition: 7.2.2.1 Extrapolationn, CIE 167:2005 Recommended Practice for Tabulating Spectral Data for Use in Colour Computations: 10. EXTRAPOLATION (Last accessed 28 May 2014)

• Bruce Lindbloom, XYZ to xyY (Last accessed 24 February 2014)
• Bruce Lindbloom, xyY to XYZ (Last accessed 24 February 2014)
• XYZ to UCS (Last accessed 24 February 2014)
• UCS to XYZ (Last accessed 24 February 2014)
• UCS to uv (Last accessed 24 February 2014)
• UCS uv to xy (Last accessed 24 February 2014)
• XYZ to UVW (Last accessed 10 June 2014)
• Bruce Lindbloom, XYZ to Luv (Last accessed 24 February 2014)
• Bruce Lindbloom, Luv to XYZ (Last accessed 24 February 2014)
• Luv to uv (Last accessed 24 February 2014)
• Luv uv to xy (Last accessed 24 February 2014)
• Bruce Lindbloom, Luv to LCHuv (Last accessed 24 February 2014)
• Bruce Lindbloom, LCHuv to Luv (Last accessed 24 February 2014)
• Bruce Lindbloom, XYZ to Lab (Last accessed 24 February 2014)
• Bruce Lindbloom, Lab to XYZ (Last accessed 24 February 2014)
• Bruce Lindbloom, Lab to LCHab (Last accessed 24 February 2014)
• Bruce Lindbloom, LCHab to Lab (Last accessed 24 February 2014)
• Paul Centore, xyY to Munsell Colour (Last accessed 26 July 2014)
• Paul Centore, Munsell Colour to xyY (Last accessed 26 July 2014)