class colour.Nayatani95_Specification[source]

Defines the Nayatani (1995) colour appearance model specification.

This specification has field names consistent with the remaining colour appearance models in colour.appearance but diverge from Fairchild (2013) reference.

  • L_star_P (numeric or array_like) – Correlate of achromatic Lightness \(L_p^\star\).
  • C (numeric or array_like) – Correlate of chroma \(C\).
  • h (numeric or array_like) – Hue angle \(\theta\) in degrees.
  • s (numeric or array_like) – Correlate of saturation \(S\).
  • Q (numeric or array_like) – Correlate of brightness \(B_r\).
  • M (numeric or array_like) – Correlate of colourfulness \(M\).
  • H (numeric or array_like) – Hue \(h\) quadrature \(H\).
  • HC (numeric or array_like) – Hue \(h\) composition \(H_C\).
  • L_star_N (numeric or array_like) – Correlate of normalised achromatic Lightness \(L_n^\star\).


  • This specification is the one used in the current model implementation.


[Fai13g], [NSY95]

Create new instance of Nayatani95_Specification(L_star_P, C, h, s, Q, M, H, HC, L_star_N)


Initialize self. See help(type(self)) for accurate signature.


count Return number of occurrences of value.
index Return first index of value.


C Alias for field number 1
H Alias for field number 6
HC Alias for field number 7
L_star_N Alias for field number 8
L_star_P Alias for field number 0
M Alias for field number 5
Q Alias for field number 4
h Alias for field number 2
s Alias for field number 3