(from opaque) inability to be seen through; the opposite of transparency. In a graphical image, objects with low opacity are partly transparent (see ghosting). Many special effects are implemented by creating a new image, with opacity under the control of the user, and superimposing it on the existing image.
characteristic of paper that can be printed on one side without the image showing through on the other side. The thicker the paper stock, the greater the opacity. Print products made with a relief (raised surface) printing plate, which pushes ink onto the surface of the paper, must be printed on paper with a high degree of opacity. Opacity is important to the functioning of optical character recognition scanners, since they are highly sensitive to light and any stray marks that may show through the paper.
