Xerography

a copying process in which an ELECTROSTATIC image is formed on a surface when exposed to an optical image. A powder mix of GRAPHITE and a thermoplastic resin of opposite charge to the electrostatic image is dusted on to the surface and the particles cling to the charged areas. The image is then transferred to a sheet of paper; again through use of opposite charges, and the image is fixed by heat.

Taken from Dictionary of Science

Aberration

is what happens in physics when a lens (or curved mirror) does not produce a true image. It is caused by the light rays from any point on the object being viewed forming an image (focusing) at slightly different positions. In astronomy, aberration refers to the apparent change in position of a star. This is due to the fixed speed of light travelling from the star and the movement of the person looking at the star, because the Earth is moving in its orbit.

Taken from Dictionary of Science