colour.quality.CQS_Specification

class colour.quality.CQS_Specification[source]

Defines the Colour Quality Scale (CQS) colour quality specification.

Parameters:
  • name (unicode) – Name of the test spectral power distribution.
  • Q_a (numeric) – Colour quality scale \(Q_a\).
  • Q_f (numeric) – Colour fidelity scale \(Q_f\) intended to evaluate the fidelity of object colour appearances (compared to the reference illuminant of the same correlated colour temperature and illuminance).
  • Q_p (numeric) – Colour preference scale \(Q_p\) similar to colour quality scale \(Q_a\) but placing additional weight on preference of object colour appearance. This metric is based on the notion that increases in chroma are generally preferred and should be rewarded.
  • Q_g (numeric) – Gamut area scale \(Q_g\) representing the relative gamut formed by the (\(a^*\), \(b^*\)) coordinates of the 15 samples illuminated by the test light source in the CIE L*a*b* object colourspace.
  • Q_d (numeric) – Relative gamut area scale \(Q_d\).
  • Q_as (dict) – Individual Colour Quality Scale (CQS) data for each sample.
  • colorimetry_data (tuple) – Colorimetry data for the test and reference computations.

References

Create new instance of CQS_Specification(name, Q_a, Q_f, Q_p, Q_g, Q_d, Q_as, colorimetry_data)

__init__()

x.__init__(…) initializes x; see help(type(x)) for signature

Methods

count(…)
index((value, [start, …) Raises ValueError if the value is not present.