The background is the area that surrounds the image when the size of the image is smaller than the application window. By default, the background is white; however, you can change it to any other color for a single page or for the entire document.
To change the background color:
For a single page, display the page, and then choose Edit > Page Background Color.
For the entire document, open the document,
and then choose Edit > Document Background
Color.
In the Choose Color dialog box, select Custom to enable the Choose Color button.
Click Choose Color to open the Windows color palette. Select a color or define a new one, and then click OK.
Click OK again to assign the new color to the page or document background.