The eraser dialog allows you to erase parts of an image, by making them transparent.
It does this by applying an alpha mask to the file. An alpha mask is a black and white image used to modify the transparency of another image. White areas in the mask will be fully visible, and black parts in the mask will be invisible. Gray parts will be translucent: the more white they are, the more visible the corresponding parts in the image will be.
Note: The eraser is non-destructive. It does not make any changes to the original image file. You can make as many changes to the eraser mask as you want without losing any quality in your original image.
Tip: This dialog is accessible from the Effects > Eraser program menu.
A preview of the selected image.
Tip: The preview window supports zooming and moving. Since the left mouse button is used for erasing, you can move the preview image around using the right mouse button.
Switch between "erase" mode and "un-erase" mode. This determines whether left-clicking in the preview area will erase the image or restore its visibility at that location.
Tip: You can also hold the Ctrl key down at any time to toggle between "erase" and "un-erase" modes.
Switch between drawing with a round eraser or a square eraser.
Show a preview of the image with the eraser mask applied. You can de-select this option to see the actual black and white alpha mask.
Saves the current alpha mask as an image file.
Tip: Any masks you save from the eraser dialog can be applied to photos as shapes.
Loads an alpha mask in from an image file.
Note: You can load any shape file into the eraser dialog.
Resets the eraser by clearing the alpha mask all to white so you can start over from the beginning.
Note: This will undo any changes you've made -- in fact it will completely remove any "erased" parts, restoring the image to its original self.
The overall diameter of the brush, in pixels.
Tip: You can also change the brush size by holding the Shift key and rolling the mouse wheel up or down.
How "soft" the edges of the brush should be.
Tip: You can also change the softness by holding the Ctrl key and rolling the mouse wheel up or down.
How transparent each "stamp" of the eraser brush will be. Moving the slider to the right will make it so drawing in the preview area applies increasing amounts of transparency, allowing you to create translucent areas in a photo, or fine-tune the softness at the edge of a cutout.
Toggle between erase and un-erase when you left click.
Erase in a straight line from the last point you left-clicked to the next point you left click.
Invert the alpha mask, making all white parts black, and all black parts white. (Like the "Invert shape" option for a custom shape, but permanent.)
Decrease the brush size.
Increase the brush size.
Decrease the brush softness.
Increase the brush softness.
Temporarily set the brush size to 1 pixel.
Temporarily set the brush size to 100 pixels.
Temporarily set the brush size to 200 pixels.
Temporarily double the current brush size.
Temporarily triple the current brush size.