Letter | Published:

The Number of Discriminable Colours


ALTHOUGH a calculation of the approximate number of discriminable colours must depend upon the individual concerned, 'normal' persons may be expected to furnish data which agree to the correct order of magnitude. The method used here involves the choice of an arbitrary colour solid, the well-known Titchener-Ebbhighaus double pyramid, to which available experimental data are applied with simplifying assumptions, in order that ordinary geometry may be used in the calculations. A straight line connecting the apexes of this double pyramid represents the black-white, or brilliance series ; the saturation series is represented by lines running from the central axis to the surface ; and the hue series is given by lines on the surface of the figure parallel to the base.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    König, A., Z. für Psych, u. Physiol. der Sinnesorg., 8, 375 (1895).

  2. 2

    Jones, L. A., J. Opt. Soc. Amer., 1, 63 (1917).

  3. 3

    Smith, F. O., J. Exper. Psych., 8, 381 (1925).

  4. 4

    Geissler, L. R., Amer. J. Psych., 24, 171 (1913).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.