# Lumen

> The unit of luminous flux.

## Definition

* **Type:** Field
* **Namespace:** [UnityEngine.Rendering](/engine/6000.0/script-reference/unityengine/rendering.md)
* **Assembly:** UnityEngine.CoreModule

```csharp
Lumen = 0
```

### Remarks

Describes the total amount of visible light that a light source emits in all directions. When you use this unit, the amount of visible light is independent of the source's size meaning the illumination level of a Scene does not change depending on the size of a light source. However, highlights that a light source produces dim as the area of the light source increases. This is because the same power is spread across a larger area.

A light source that emits 1 candela of luminous intensity from an area of 1 steradian has a luminous flux of 1 lumen.

Compatible light types: [LightType.Point](/engine/6000.0/script-reference/unityengine/lighttype/point.md), [LightType.Spot](/engine/6000.0/script-reference/unityengine/lighttype/spot.md), [LightType.Pyramid](/engine/6000.0/script-reference/unityengine/lighttype/pyramid.md), [LightType.Rectangle](/engine/6000.0/script-reference/unityengine/lighttype/rectangle.md), [LightType.Disc](/engine/6000.0/script-reference/unityengine/lighttype/disc.md), [LightType.Tube](/engine/6000.0/script-reference/unityengine/lighttype/tube.md).

Additional Resources: [Light.lightUnit](/engine/6000.0/script-reference/unityengine/light/lightunit.md), [light component](/engine/6000.0/manual/lighting-overview/lighting-birp/class-light.md).