Color Coordinate Conversion

COLORS is a FORTRAN90 library which converts color data from one system to another.

The color coordinate systems considered include CIELAB, CIELUV, CIExyY, CIEXYZ, CMY, CMYK, HLS, HSI, HSV, HVC, LCC, NCS, PhotoYCC, RGB, Y'CbCr, Y'IQ, Y'PbPr and Y'UV.

Color specification and conversion is a suprisingly difficult subject. For a particular situation, getting more red just means increasing some number. But to accurately try to take a given color that shows up on one computer monitor screen, write down the color specification numbers and the illumination, and then figure out the corresponding color specification numbers in a different color system on a different device (a printer, a television) with a different illumination is actually an extraordinary art.


The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.


COLORS is available in a FORTRAN90 version.

Related Data and Programs:

COLOR, a dataset directory which describes colors by name, triples of integers between 0 and 255, or triples of real numbers between 0 and 1.


  1. George Agoston,
    Color Theory and Its Application in Art and Design,
    Second edition,
    Springer, 1987,
    ISBN: 038709654X,
    LC: QC495.A32.
  2. Wayne Brown, Barry Shepherd,
    Graphics File Formats,
    Manning Publications, 1995,
    ISBN: 1884777007,
    LC: T385.B777.
  3. James Foley, Andries vanDam, Steven Feiner, John Hughes,
    Computer Graphics, Principles and Practice,
    Second Edition,
    Addison Wesley, 1995,
    ISBN: 0201848406,
    LC: T385.C5735.
  4. Brand Fortner,
    Number by Colors, A Guide to Using Color to Understand Technical Data,
    Springer, 1997,
    ISBN: 0387946853,
    LC: QC495.F6.
  5. Edward Giorgianni, Thomas Madden,
    Digital Color Management, Encoding Solutions,
    Addison Wesley, 1998,
    ISBN: 0201634260,
    LC: TA1637.G56.
  6. Jonas Gomes, Luiz Velho,
    Image Processing for Computer Graphics,
    Springer, 1997,
    ISBN: 0387948546,
    LC: T385.G65.
  7. Roy Hall,
    Illumination and Color in Computer Generated Imagery,
    Springer, 1989,
    ISBN: 0387967745,
    LC: T385.H327.
  8. International Electrotechnical Commission,
    The sRGB standard,
    Standard IEC 61966-2-1,
  9. Deane Judd, Gunter Wyszecki,
    Color in Business, Science, and Industry,
    Wiley, 1975,
    ISBN: 0471452122,
    LC: QC495.J79.
  10. Olof Kylander, Karin Kylander,
    GIMP: The Official Handbook,
    Coriolis Open Press, 1999,
    ISBN: 1576105202,
    LC: T385.K866.
  11. David Martindale, Alan Paeth,
    Television Color Encoding and Hot Broadcast Colors,
    in Graphics Gems II,
    edited by James Arvo,
    Academic Press, 1991,
    ISBN: 0120644819,
    LC: T385.G6972.
  12. Calvin McCamy, H Marcus, JG Davidson,
    A Color Rendition Chart,
    Journal of Applied Photographic Engineering,
    Volume 11, Number 3, 1976, pages 95-99.
  13. Guenter Wyszecki, Walter Stiles,
    Color Science: Concepts and Methods, Quantitative Data and Formulas,
    John Wiley, 1967,
    ISBN: 0-471-02106-7,
    LC: QC495.W88.

Source Code:

Examples and Tests:

List of Routines:

You can go up one level to the FORTRAN90 source codes.

Last revised on 31 December 2010.