---
title: "ChannelsProvider..::.AddAlpha Method (Bitmap)"
canonical: https://www.graphicsmill.com/docs/gm5/M_Aurigma_GraphicsMill_ChannelsProvider_AddAlpha_1_fd4033ef.htm
product: "Graphics Mill 5.5 for .NET"
---

This documentation is for the old version. [Go to the latest Graphics Mill docs](https://www.graphicsmill.com/docs/gm/)

# ChannelsProvider.AddAlpha Method (Bitmap)
 
Appends bitmap alpha channel to current bitmap.
 
**Namespace:** [Aurigma.GraphicsMill](https://www.graphicsmill.com/docs/gm5/N_Aurigma_GraphicsMill.htm.md)
 **Assembly:** Aurigma.GraphicsMill (in Aurigma.GraphicsMill.dll)
 
## Syntax
  
```
Public Sub AddAlpha ( _alpha As Bitmap _
)
```
 
```csharp
public void AddAlpha(Bitmap alpha
)
```
 
### Parameters
 
 - alpha
     - Type: [Aurigma.GraphicsMill.Bitmap](https://www.graphicsmill.com/docs/gm5/T_Aurigma_GraphicsMill_Bitmap.htm.md)
Grayscale bitmap to initialize alpha channel with. Valid bitmaps have the same dimensions and color depth as the current bitmap.
 
## Remarks
 If alpha channel is already presented in the bitmap, this method will throw an exception. To check if alpha channel is available, use [HasAlpha](https://www.graphicsmill.com/docs/gm5/P_Aurigma_GraphicsMill_Bitmap_HasAlpha.htm.md) property of the [Bitmap](https://www.graphicsmill.com/docs/gm5/T_Aurigma_GraphicsMill_Bitmap.htm.md).
   
## See Also

### Reference

- [ChannelsProvider Class](https://www.graphicsmill.com/docs/gm5/T_Aurigma_GraphicsMill_ChannelsProvider.htm.md)
- [AddAlpha Overload](https://www.graphicsmill.com/docs/gm5/O_T_Aurigma_GraphicsMill_ChannelsProvider_AddAlpha.htm.md)
- [Aurigma.GraphicsMill Namespace](https://www.graphicsmill.com/docs/gm5/N_Aurigma_GraphicsMill.htm.md)