# Overlay enum

Namespace: [Grasshopper2.Extensions](https://developer.rhino3d.com/api/gh2/namespace/grasshopper2.extensions.md) · Assembly: [Grasshopper2](https://developer.rhino3d.com/api/gh2/assembly/grasshopper2.md)

```cs
public enum Overlay
```

Enumerates the possible overlay methods.

## Values

| Name | Value | Description |
| --- | --- | --- |
| Stain | 0 | Channel values are multiplied, giving a stained glass effect. |
| Bleach | 1 | Channel values are added, giving a bleaching effect. |
| Darken | 2 | Channel values are subtracted, giving a darkening effect. |
| ImposeAlpha | 3 | The alpha value of the overlay is imposed on the target colour. |
| ImposeHue | 4 | The hue value of the overlay is imposed on the luminance and saturation of the target image. |
| ImposeLuminance | 5 | The luminance value of the overlay is imposed on the hue and saturation of the target image. |
| ImposeSaturation | 6 | The saturation value of the overlay is imposed on the hue and luminance of the target image. |
| Minimum | 7 | If the overlay is darker, it is copied, otherwise the target remains the same. |
| Maximum | 8 | If the overlay is lighter, it is copied, otherwise the target remains the same. |