---
title: "TiffReader.TreatFirstExtraChannelAsAlpha Property "
canonical: https://www.graphicsmill.com/docs/gm/P_Aurigma_GraphicsMill_Codecs_TiffReader_TreatFirstExtraChannelAsAlpha.htm
product: "Graphics Mill"
---

# TiffReader.TreatFirstExtraChannelAsAlpha Property 
 
Gets or sets a value indicating whether the reader should interpret the first extra channel as alpha channel in pixel data.
 
**Namespace:** [Aurigma.GraphicsMill.Codecs](https://www.graphicsmill.com/docs/gm/N_Aurigma_GraphicsMill_Codecs.htm.md)
 **Assembly:** Aurigma.GraphicsMill (in Aurigma.GraphicsMill.dll)
 
## Syntax
  
```csharp
public bool TreatFirstExtraChannelAsAlpha { get; set; }
```
 
### Property Value
 `true` if the reader interprets the first extra channel as alpha; otherwise, `false`. The default value is `true`.
 
## Remarks
  
For example, assume you read an image contained three color channels (RGB) and two extra ones. If this property is `true`, the image loaded from frame using [GetBitmap()](https://www.graphicsmill.com/docs/gm/M_Aurigma_GraphicsMill_Codecs_Frame_GetBitmap.htm.md) method will be interpreted as ARGB (RGB + alpha). [ExtraChannels](https://www.graphicsmill.com/docs/gm/P_Aurigma_GraphicsMill_Codecs_TiffFrame_ExtraChannels.htm.md) collection will contain one extra channel in this case. Otherwise, if the TreatFirstExtraChannelAsAlpha property is `false`, it will be interpreted as RGB with two extra channels.
   
## See Also

### Reference

- [TiffReader Class](https://www.graphicsmill.com/docs/gm/T_Aurigma_GraphicsMill_Codecs_TiffReader.htm.md)
- [Aurigma.GraphicsMill.Codecs Namespace](https://www.graphicsmill.com/docs/gm/N_Aurigma_GraphicsMill_Codecs.htm.md)

### Manual

- [Working with TIFF Extra Channels](https://www.graphicsmill.com/docs/gm/working-with-tiff-extra-channels.htm.md)