Laser graphics concern the art of creating three-dimensional images projected onto screens, walls, buildings, or even mountains.

This is not like watching video or film--the intense color and contrast of lasers, combined with the unique glittering qualities of the light, transport viewers to another world.

Laser graphics begin with a small dot of laser light. Using tiny scanning mirrors, that dot is moved about so rapidly the human eye perceives a solid line of light. Other times, a stationary beam and special optics create abstract patterns. The basic types of laser graphics are:

• Representational imagery: using computer-controlled scanning mirrors, laser show expert's can project complex line artwork. The graphics come to life with a mix of hand-animation and digital computer tools. Often, imagery is directly imported from files created for computer graphics applications. Although most imagery is vector-based, raster projection can be used to create video-like images in laser light.

• Abstract Imagery: Before computers, laser show experts used analog synthesizers to create other-worldly shapes that were made to dance to music in live performances. Abstracts are still alive and well, created now with both analog and digital tools.

• Lumia: When the laser beam is projected through specialized optics, cloud-like wisps of light are created that can be made to float across ceilings and domes. Called lumia, these effects can stand by themselves or may be combined with representational and abstract imagery.

• Diffraction Gratings: These specialized optics are used to project a wide variety of patterns--from simple circles to complex galaxy-like star-fields. All that is needed is a single beam of laser light and an optic no bigger than a postage stamp.