Observers and Illuminants

Illuminants and observer angles are used in all color spaces that use reflective (instead of transmissive) light. Here are a few brief overviews of what these are and what they do:

• Understanding Standard Illuminants in Color Measurement - Konica Minolta
• What is Meant by the Term “Observer Angle”? - XRite

To adjust the illuminants and/or observer angles on a color:

lab = LabColor(0.1, 0.2, 0.3, observer='10', illuminant='d65')

Two-degree observer angle

These illuminants can be used with observer='2', for the color spaces that require illuminant/observer:

• 'a'
• 'b'
• 'c'
• 'd50'
• 'd55'
• 'd65'
• 'd75'
• 'e'
• 'f2'
• 'f7'
• 'f11'

Ten-degree observer angle

These illuminants can be used with observer='10', for the color spaces that require illuminant/observer:

• 'd50'
• 'd55'
• 'd65'
• 'd75'