1. Open two images, the one you want to add the mask to (host) and the one you want to be the mask (source).
2. Make the host image the active image
3. Click on mask/new/from image

note:If the host image and source image have different dimensions, the mask will be automatically resized to match the host image.

settings:

1. source: The window you want to create the mask from not the window you're adding the mask to.
2. create mask from source luminance (we will delve into the other settings at a later date)
3. click ok, the new mask will be attached to your host image

1. click view/through mask
2. click mask/invert to preview the effect with opposite areas masked

5. For the finished effect to appear the same as the preview, you must click mask/invert before you adjust the brightness/contrast
So go ahead and click on mask/invert now.
Note: that's mask/invert not selections/invert

6.Select Colors/Adjust/Brightness-Contrast (Note: This is the 'important' step. If you try to save your image without this step, all you'll get is the host image without the mask

Settings:

• brightness -100
• contast 0

Depending on the images used, you may well be finished with your graphic at this point. Mine is too dark and I want to make some further adjustments to it.

7. Select:Colors | Adjust | Highlight/Midtone/Shadow

Settings:

• Highlight:47
• Midtone:60
• Shadow: 0

click for full size version
8. I added a spotlight using Greg's Factory Output, Vol.II,Spotlight

9. Softened Image ("Image | Normal Filters | Soften

10. Select: Colors | Adjust | Red/Green/Blue

Settings:

• Red: 5
• Green: 0
• Blue: 87

11. Stretch the available light using Colors | Histogram Functions | Stretch

12. Save

Creating Masks from a Selection coming soon!