Using Alpha Arithmetic

Use Alpha Arithmetic to apply specific mathematical operations to the alpha channel.

To apply an Alpha Arithmetic filter:

1. Select the layer.
2. Choose Operators | Channel | Alpha Arithmetic.

The Alpha Arithmetic Controls panel appears.

The Alpha Arithmetic Controls panel contains the following elements.

Operator

Specifies which mathematical operation is applied to the alpha channel. For a complete list of options, see Operator List Options.

Operand

Specifies the intensity of the selected operator. The effect depends on the mathematical operator specified. In most cases, 0% applies no mathematical operations, while 100% is full intensity of the selected operator.

Undefined Areas

Specifies the color used to fill in the blank (0% opacity) areas of the image. Click the Pick button to select a color from the screen, or click the color box to choose a color from the color picker.

Blend

Specifies the percentage amount for which the channel effect is visible over the original layer. Values below 100% allow you to see the original layer.