Using the alpha channel

An alpha band acts as a transparency mask, providing a transparency value for each pixel. An alpha band can be toggled on or off for multiple-band raster datasets rendered with the RGB Composite renderer.

Steps:

1. Right-click the raster layer you want to change the alpha band for in the table of contents and click Properties.
2. Click the Symbology tab.
3. Click RGB Composite.
4. To turn the alpha band on, check the Alpha channel box and choose a band to use.

   To turn the alpha band off, uncheck the box for the Alpha channel.

5. Click OK.