colour.chromatic_adaptation#

colour.chromatic_adaptation(XYZ: ArrayLike, XYZ_w: ArrayLike, XYZ_wr: ArrayLike, method: Literal['CIE 1994', 'CMCCAT2000', 'Fairchild 1990', 'Li 2025', 'Von Kries', 'Zhai 2018', 'vK20'] | str = 'Von Kries', **kwargs: Any) → NDArrayFloat[source]#

Adapt the specified stimulus CIE XYZ tristimulus values from test viewing conditions to reference viewing conditions using the specified chromatic adaptation method.

Parameters:

XYZ (ArrayLike) – CIE XYZ tristimulus values of stimulus to adapt.
XYZ_w (ArrayLike) – Test viewing condition CIE XYZ tristimulus values of the whitepoint.
XYZ_wr (ArrayLike) – Reference viewing condition CIE XYZ tristimulus values of the whitepoint.
method (Literal['CIE 1994', 'CMCCAT2000', 'Fairchild 1990', 'Li 2025', 'Von Kries', 'Zhai 2018', 'vK20'] | str) – Computation method.
E_o1 – {colour.adaptation.chromatic_adaptation_CIE1994()}, Test illuminance \(E_{o1}\) in \(lux\).
E_o2 – {colour.adaptation.chromatic_adaptation_CIE1994()}, Reference illuminance \(E_{o2}\) in \(lux\).
n – {colour.adaptation.chromatic_adaptation_CIE1994()}, Noise component in fundamental primary system.
Y_o – {colour.adaptation.chromatic_adaptation_CIE1994()}, Luminance factor \(Y_o\) of achromatic background normalised to domain [0.18, 1] in ‘Reference’ domain-range scale.
direction – {colour.adaptation.chromatic_adaptation_CMCCAT2000()}, Chromatic adaptation direction.
L_A1 – {colour.adaptation.chromatic_adaptation_CMCCAT2000()}, Luminance of test adapting field \(L_{A1}\) in \(cd/m^2\).
L_A2 – {colour.adaptation.chromatic_adaptation_CMCCAT2000()}, Luminance of reference adapting field \(L_{A2}\) in \(cd/m^2\).
surround – {colour.adaptation.chromatic_adaptation_CMCCAT2000()}, Surround viewing conditions induction factors.
discount_illuminant – {colour.adaptation.chromatic_adaptation_Fairchild1990()}, Truth value indicating if the illuminant should be discounted.
Y_n – {colour.adaptation.chromatic_adaptation_Fairchild1990()}, Luminance \(Y_n\) of test adapting stimulus in \(cd/m^2\).
L_A – {colour.adaptation.chromatic_adaptation_Li2025()}, Adapting field luminance \(L_A\) in \(cd/m^2\).
F_surround – {colour.adaptation.chromatic_adaptation_Li2025()}, Maximum degree of adaptation \(F\) from surround viewing conditions.
discount_illuminant – {colour.adaptation.chromatic_adaptation_Li2025()}, Truth value indicating if the illuminant should be discounted.
D_b – {colour.adaptation.chromatic_adaptation_Zhai2018()}, Degree of adaptation \(D_\beta\) of input illuminant \(\beta\).
D_d – {colour.adaptation.chromatic_adaptation_Zhai2018()}, Degree of adaptation \(D_\Delta\) of output illuminant \(\Delta\).
XYZ_r – {colour.adaptation.chromatic_adaptation_vK20()}, Reference viewing conditions CIE XYZ tristimulus values of whitepoint.
coefficients – {colour.adaptation.chromatic_adaptation_vK20()}, vK20 degree of adaptation coefficients.
transform – {colour.adaptation.chromatic_adaptation_VonKries(), colour.adaptation.chromatic_adaptation_vK20(), colour.adaptation.chromatic_adaptation_Zhai2018()}, Chromatic adaptation transform.
XYZ_wo – {colour.adaptation.chromatic_adaptation_Zhai2018()}, Baseline illuminant (\(BI\)) \(o\).
kwargs (Any)

Returns:

CIE XYZ tristimulus values of the stimulus corresponding colour.

Return type:

numpy.ndarray

Notes

Domain	Scale - Reference	Scale - 1
`XYZ`	1	1
`XYZ_w`	1	1
`XYZ_wr`	1	1
`XYZ_wo`	1	1
`Y_o`	1	1

Range	Scale - Reference	Scale - 1
`XYZ_c`	1	1

References

[CIET13294], [Fai91], [Fai13f], [Fai13a], [LLRH02], [Li25], [WRC12d]

Examples

Von Kries chromatic adaptation:

>>> import numpy as np
>>> XYZ = np.array([0.20654008, 0.12197225, 0.05136952])
>>> XYZ_w = np.array([0.95045593, 1.00000000, 1.08905775])
>>> XYZ_wr = np.array([0.96429568, 1.00000000, 0.82510460])
>>> chromatic_adaptation(XYZ, XYZ_w, XYZ_wr)
...
array([0.2163881..., 0.1257    , 0.0384749...])

vK2020 chromatic adaptation:

>>> XYZ_w = np.array([0.95045593, 1.00000000, 1.08905775])
>>> XYZ_wr = np.array([0.96429568, 1.00000000, 0.82510460])
>>> chromatic_adaptation(XYZ, XYZ_w, XYZ_wr, method="vK20")
...
array([0.2146884..., 0.1245616..., 0.0466255...])

CIE 1994 chromatic adaptation, requires extra kwargs:

>>> XYZ = np.array([0.2800, 0.2126, 0.0527])
>>> XYZ_w = np.array([1.09867452, 1.00000000, 0.35591556])
>>> XYZ_wr = np.array([0.95045593, 1.00000000, 1.08905775])
>>> Y_o = 0.20
>>> E_o = 1000
>>> chromatic_adaptation(
...     XYZ, XYZ_w, XYZ_wr, method="CIE 1994", Y_o=Y_o, E_o1=E_o, E_o2=E_o
... )
...
array([0.2403379..., 0.2115621..., 0.1764301...])

CMCCAT2000 chromatic adaptation, requires extra kwargs:

>>> XYZ = np.array([0.2248, 0.2274, 0.0854])
>>> XYZ_w = np.array([1.1115, 1.0000, 0.3520])
>>> XYZ_wr = np.array([0.9481, 1.0000, 1.0730])
>>> L_A = 200
>>> chromatic_adaptation(
...     XYZ, XYZ_w, XYZ_wr, method="CMCCAT2000", L_A1=L_A, L_A2=L_A
... )
...
array([0.1952698..., 0.2306834..., 0.2497175...])

Fairchild (1990) chromatic adaptation, requires extra kwargs:

>>> XYZ = np.array([0.1953, 0.2307, 0.2497])
>>> Y_n = 200
>>> chromatic_adaptation(XYZ, XYZ_w, XYZ_wr, method="Fairchild 1990", Y_n=Y_n)
...
array([0.2332526..., 0.2332455..., 0.7611593...])

Li (2025) chromatic adaptation:

>>> XYZ = np.array([0.1953, 0.2307, 0.2497])
>>> L_A = 64
>>> F_surround = 1.0
>>> chromatic_adaptation(
...     XYZ, XYZ_w, XYZ_wr, method="Li 2025", L_A=L_A, F_surround=F_surround
... )
...
array([0.2039701..., 0.2304747..., 0.6783065...])

Zhai and Luo (2018) chromatic adaptation:

>>> XYZ = np.array([0.20654008, 0.12197225, 0.05136952])
>>> XYZ_w = np.array([0.95045593, 1.00000000, 1.08905775])
>>> XYZ_wr = np.array([0.96429568, 1.00000000, 0.82510460])
>>> chromatic_adaptation(XYZ, XYZ_w, XYZ_wr, method="Zhai 2018")
...
array([0.2163881..., 0.1257    , 0.0384749...])
>>> chromatic_adaptation(
...     XYZ,
...     XYZ_w,
...     XYZ_wr,
...     method="Zhai 2018",
...     D_b=0.9,
...     XYZ_wo=np.array([100, 100, 100]),
... )
...
array([0.2152436..., 0.1253522..., 0.0388406...])

colour.chromatic_adaptation#

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