About   |   Glossary   |   Site map   |   Help   |   Credits   |   Contact
 Home   Color   Describing and Measuring Color  


Describing and Measuring Color

Every color can be described in physical terms as light waves of a specific wavelength and intensity .For example the hue of light wavelengths in the range of 560 to 580 nm is green, which we perceive as a specific color . Yet color is more than mere physical data. It is the percept of color that we sense and react to.



Physical aspects
When describing color, its physical and psychological
aspects alike must be considered.		     The type of light source, the 
wavelengths it generates
and its intensity.

The spectrum generated by a
standard incandescent lamp.		     Filtering of certain wavelengths 
(subtractive color mixing).

The color of the avocado looks
different when seen through
color filters.


Selective color reflection, determined 
by the type and quality of pigments 
on the illuminated surface.		  

The size of the object and the
visual context (background).
   pic076_05_450

Other colors in the environment of the object.

Psychological Aspects
Color, although derived from measurable physical phenomena, is a subjective psychological phenomenon which is perceived by the human eye as a certain color. Color is perceived as a whole whose separate characteristics are difficult to discern, but can nevertheless be described. The perception of color depends on the following variables:

Hue - The spectral location of the color,  
i.e. the range of wavelengths.



The hue of orange consists of the wavelengths 590 to 630 nm.

 

Saturation - The purity or distinction
of the color, for example how
exclusively red is a  certain shade of red.

Variations of saturation from primary red to black.

  Brightness (or Value) - How bright or dark  a color appears.



Variations of brightness
from white to primary red.

The combined qualities of hue and saturation are referred to as chroma.

Various systems have been devised to characterize and measure color, emphasizing different physical and psychological considerations.



Munsell System
Color Temperature
Correlated Color Temperature
Color Rendering Index
The CIE System