The quality or state of being white; white color,
or freedom from darkness or obscurity on the surface. --Chaucer.
[1913 Webster]
Want of a sanguineous tinge; paleness; as from
terror, grief, etc. "The whiteness in thy cheek." --Shak. [1913
Webster]
Freedom from stain or blemish; purity; cleanness.
[1913 Webster] He had kept The whiteness of his soul, and thus men
o'er him wept. --Byron. [1913 Webster]
Nakedness. [Obs.] --Chapman. [1913 Webster]
(Zool.) A flock of swans. [1913 Webster]
Word Net
whiteness n : the quality or state of the achromatic color of greatest lightness (bearing the least resemblance to black) [syn: white] [ant: black]English
Pronunciation
Noun
- The state of being white.
In colorimetry, whiteness is
the degree to which a surface is white. An example of its use might
be to quantitatively compare two pieces of paper which appear white
viewed individually, but not when juxtaposed.
The
International Commission on Illumination describes it in the
following terms:
To promote uniformity of
practice in the evaluation of whiteness of surface colors, it is
recommended that the formulæ for whiteness, W2 or W10, and for
tint, Tw,2 or Tw,10, given
below, be used for comparisons of the whiteness of samples
evaluated for CIE standard
illuminant D65. The application of
the formulae is restricted to samples that are called "white"
commercially, that do not differ much in color and fluorescence, and
that are measured on the same instrument at nearly the same time.
Within these restrictions, the formulæ provide relative, but not
absolute, evaluations of whiteness, that are adequate for
commercial use, when employing measuring instruments having
suitable modern and commercially available facilities.CIE
Publication 15:2004
Calculation
W_2=Y_2+800(x_-x_2)+1700(y_-y_2)W_=Y_+800(x_-x_)+1700(y_-y_)
T_=1000(x_-x_2)-650(y_-y_2)
T_=900(x_-x_)-650(y_-y_)
where
- Y is the Y tristimulus value (relative luminance),
- (x,y) is the chromaticity coordinate in the CIE 1931 color space
- (xn,yn) is the chromaticity coordinate of the perfect diffuser (reference white)
The numbers in the subscript indicate the
observer: two for the CIE 1931 standard
observer and ten for the CIE 1964 standard observer.
Notes
- W increases with whiteness, reaching 100 for the perfect diffuser.
- The tint is green for positive T and red for negative T.
- Equal differences in W may not appear equally different.
See also
References
- Colorimetry: Understanding the CIE System
External links
- ISO 105-J02:1997 Textiles -- Tests for colour fastness -- Part J02: Instrumental assessment of relative whiteness
- ISO 11475:2004 Paper and board -- Determination of CIE whiteness, D65/10 degrees (outdoor daylight)
- ISO 11476:2000 Paper and board -- Determination of CIE-whiteness, C/2 degree (indoor illumination conditions)
- ISO/AWI 11476 Paper and board -- Determination of CIE-whiteness, C/2 degree (indoor illumination conditions)