---
title: "TiffExtraChannelCollection Class"
canonical: https://www.graphicsmill.com/docs/gm/T_Aurigma_GraphicsMill_Codecs_TiffExtraChannelCollection.htm
product: "Graphics Mill"
---

# TiffExtraChannelCollection Class
 
Represents a collection of TIFF extra channels.
 
**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 sealed class TiffExtraChannelCollection : Collection<TiffExtraChannelEntry>
```
 
## Remarks
 The collection contains all extra channels associated with the TIFF page. Using this property you can either obtain all extra channels from the page or write some channels in addition to primary ones.
 
## Examples
  
The following code adds a JPEG image to a TIFF image as an unassociated alpha extra channel, and saves the resulting TIFF image.
 
```csharp
using (var reader = new TiffReader(@"Images\BusinessCard.tif"))
using (var writer = new TiffWriter(@"Images\Output\result.tif"))
{
    // Load bitmap for the extra channel.
    // Note: image for extra channel must be gray scale and have the same dimensions and DPI as the source one. 
    using (var extraBitmap = new Bitmap(@"Images\extraChannel.jpg"))
    {
        // Create extra channel options based on extraBitmap.
        var extraChannel = new TiffExtraChannelEntry(extraBitmap, TiffChannelType.Alpha);

        writer.ExtraChannels.Add(extraChannel);
        Pipeline.Run(reader + writer);
    }
}
```
 
## Inheritance Hierarchy
  
- System.Object
    - System.Collections.ObjectModel.Collection &lt; [TiffExtraChannelEntry](https://www.graphicsmill.com/docs/gm/T_Aurigma_GraphicsMill_Codecs_TiffExtraChannelEntry.htm.md) &gt;
        - Aurigma.GraphicsMill.Codecs.TiffExtraChannelCollection
 
## Thread Safety
 Static members of this type are not safe for multi-threaded operations. Instance members of this type are not safe for multi-threaded operations.
   
## See Also

### Reference

- [TiffExtraChannelCollection Members](https://www.graphicsmill.com/docs/gm/AllMembers_T_Aurigma_GraphicsMill_Codecs_TiffExtraChannelCollection.htm.md)
- [Aurigma.GraphicsMill.Codecs Namespace](https://www.graphicsmill.com/docs/gm/N_Aurigma_GraphicsMill_Codecs.htm.md)

### Manual

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