Specifying opacity is as easy as specifying the shade of a color. In fact, wherever you can pick a color — in the Colors palette, the Measurements palette, the Style menu, various tabs of the Modify dialog box (Item menu), the Character Attributes dialog box (Style > Character), and more — you can enter an opacity value from 0% (transparent) to 100% (opaque) in 0.1% increments. To specify opacity for a picture, enter a value in the Opacity field of the Picture tab (Item > Modify).