Object Matting

The Matting commands are helpful when a selection has been anti-aliased against a white, black or colored background, and you want to paste the selection in front of a different background.

An example. If you created a circular zone (using elliptical marquee) and filled it with white this new round is automatically antialiased. So if you create it on a black background, this produces gray pixels at the edges, which are visible against a colored background.

• Choose Object > Matting > Remove White Matte to eliminate the ghosting of white around the edges of images created on white backgrounds.
• Choose Object > Matting > Remove Black Matte to remove the ghosting of black around the edges of images created on black backgrounds.

You can also remove a colored matte using the command :

• Object > Matting > Remove Color Matte to open the color picker menu where you can choose the color of the background on the one you created your image.

It may be a good idea to have the precise color you need selected to remove the perfectly remove the matting. When cutting the selection to create an new object 

• Select the color of background of the image from the one you copy your new object

• Save it in the Color Shelf palette so that you can recall it quickly when you need it.