# 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'`