3 Choose Object > SpriteLayers > Attach Mask. Canvas creates a channel mask and both objects remain selected. The original paint object is not changed. If the paint object and the object to be masked aren’t the same size, Canvas scales the image of the paint object to fit the masked object. A channel mask created from a paint object is the same as any chan- nel mask. You can edit it the same as if you created a blank channel mask. Like any other channel mask, a channel mask created from a paint object produces transparency relative to its gray values. If the channel mask is solid white, it creates no transparency; if it is solid black, it creates 100% transparency and makes the masked object invisible. Editing channel masks You can use painting tools, filters, and image-editing commands to modify the effect of a channel mask. To edit a channel mask, the masked object must be in channel mask edit mode. Editing a channel mask is similar to editing a channel in a paint object. You can paint in the channel mask with shades of gray. You can make selections with selection tools, commands, and alpha chan- nels. You can apply image-adjustment commands and filters to the entire channel mask or to just the selected areas. To edit a channel mask 1 Select the masked object. 2 Choose Object > SpriteLayers > Edit Channel Mask. The masked object appears in channel mask edit mode. In this mode, the channel mask is active and the object is also visible. You can paint in the channel or modify it to change the transparency of the underlying object. 3 When you finish editing, press the Esc key to leave edit mode. The object remains selected. Options for channel mask editing:  You can enter channel mask edit mode using any of the following methods. With the mouse: Press Option (Mac) or Ctrl (Windows) and double- click a masked object.
Canvas 8 Help: SpriteLayer effects (11 of 24)                                                       Page #365