How to export a TIF file without an Alpha channel.

Using Prism 7 Win or Mac:

To export a tiff file without an alpha channel: choose "White" for the Background color in Prism's Export dialog,

Using Prism 6 Win or Mac:

To export a TIF (TIFF) file without an alpha channel: choose “Include color" for the "Background Color" in Prism's Export dialog.

To remove an alpha channel from an existing tiff file created by Prism using a Mac

1. Launch the program Preview, which comes with the Mac.
2. Open the TIF file.
3. Drop the File menu and choose Export (10.7 Lion) or Save As.
4. Check the option to not save the Alpha information.