In a paint object that has a visibility mask, you can erase or delete
pixels to reveal a clear background. For example, you can erase at the
edge of an image to create faded or torn edges. You can delete or
move selections to create transparent areas.
If a paint object does not have a visibility mask, areas where you drag
the Eraser tool, and selections you delete or move, become filled with
the current background color and are opaque, not clear.
When you create paint objects with painting tools or the Render or
Create commands, you can select an option to include visibility
masks.
To add a visibility mask
1
Select a paint object that does not have a visibility mask.
2
Choose Image > Add Visibility Mask. This command is not
available if a Duotone, Indexed, or Multichannel image is selected.
Adding a visibility mask does not change the appearance of a paint
object. White pixels do not become transparent, for example. When a
paint object has a visibility mask, you can select Preserve Visibility
in the Channels palette. When this option is selected, Canvas protects
clear areas from the effects of painting and image editing.
White areas of the fish image
erased to a clear background
A rectangle and
text are blocked
by an opaque
paint object in
front
A transparent
background lets
objects show
through it
Paint object backgrounds
You can create a paint object in
which the image background is
transparent or opaque.
An opaque paint object contains
opaque pixels. If the pixels are white
and the paint object is on a white
background, you wont notice that
the image is opaque. Still, the rect-
angular paint object will block
objects behind it (A).
A transparent paint object can have
a clear background that does not
block other objects (B).
Painting in an opaque image is like
painting on a wall. Painting in a
transparent image is like painting on
a window.
A
B