class colour.LLAB_Specification[source]

Defines the :math:`LLAB(l:c)` 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.

  • J (numeric or array_like) – Correlate of Lightness \(L_L\).
  • C (numeric or array_like) – Correlate of chroma \(Ch_L\).
  • h (numeric or array_like) – Hue angle \(h_L\) in degrees.
  • s (numeric or array_like) – Correlate of saturation \(s_L\).
  • M (numeric or array_like) – Correlate of colourfulness \(C_L\).
  • HC (numeric or array_like) – Hue \(h\) composition \(H^C\).
  • a (numeric or array_like) – Opponent signal \(A_L\).
  • b (numeric or array_like) – Opponent signal \(B_L\).


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


[Fairchild2013x], [Luo1996b], [Luo1996c]

Create new instance of LLAB_Specification(J, C, h, s, M, HC, a, b)


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


__init__ Initialize self.
index(value, [start, [stop]]) Raises ValueError if the value is not present.


C Alias for field number 1
HC Alias for field number 5
J Alias for field number 0
M Alias for field number 4
a Alias for field number 6
b Alias for field number 7
h Alias for field number 2
s Alias for field number 3