The Opacity Mask system takes any object, or group of objects, and uses the color (usually black to white shading) of these objects to define which parts of any other object are transparent or opaque.
Any object or group of objects can be used as an opacity mask. It can be anything from a simple shape, or blend, to a complex grouped drawing. Any black color will become 100% transparent, while white will be 100% opaque and shades in-between will create varying degrees of transparency.
Applying a Mask
There are several ways to apply an Opacity Mask.
Apply via paste
a) Select the mask, copy it so its added to the clipboard
b) Select the object, photo or group to which you wish to apply the mask
c) Click on the Edit menu followed by 'Paste opacity mask' (shift+ctrl+m)
Apply from Arrange menu
a) Place the mask over the object, photo or group you wish to apply it too.
b) Select the mask and the object, photo or group
c) Click on the Arrange menu followed by 'Apply opacity mask'
Inverting the Mask - Having applied an opacity mask, select it and press Ctrl + Alt + V
By default, Any black color will become 100% transparent, while white will be 100% opaque and shades in-between will create varying degrees of transparency. This can be reversed causing any white color to become 100% transparent, black 100% opaque.
Clipping a Mask - Having applied an opacity mask, select it and press Ctrl + Alt + c
The object photo or group the mask has been applied to will be clipped to the mask.
Some examples of Opacity masks being applied are shown in this video.
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Enhance tool | Clip | Clone | Magic erase | Photo Healing tool | Red eye | Content aware scale | Content aware zoom | Levels | Panorama | Perspective correction | Exif | Opacity masks | Photo hue | Color erase/ selection | Background Erase | Photo Effects | Shadow & Highlight controls