A parcan is a simple cylindrical can, which serves as a container for a glass bulb. The bulbs contain all the optics for the lamp within the glass envelope, and include a parabolic reflector behind the filament. Thus, the PAR(abolic) in a can - a parcan.

Parcans are widely used in environments where strong, bright colored lighting over a certain area is required. For example, dancefloors, DJ clubs, live band shows, and even at home (you've seen flood lights, right? Those are parcans).

Parcans come in different sizes, the most common being Par 56 and Par 64 (the numbers indicate size paramters for the bulb).

What are those size parameters? Well, take the PAR number and divide by eight.

For example, to calculate the size of a Par 64 can, you would use this formula:

64 divided by 8 equals 8 inches in diameter.

A Par 56 can would be:

56 divided by 8 equals 7 inches in diameter.

Bottom Line: the larger the bulb diameter, the larger the area that is illuminated.

Focusing:

Parcans only allow for limited focusing over certain areas. They can pan (go side to side) and tilt (go up and down) and the bulb can be rotated within the can. This is because the PAR(abolic) beam output of the lamp is slightly narrower across one plane.

There are also three types of bulb that can be used to give different degrees of spread - wide, medium, and narrow.

Narrow: the surface of the bulb is totally transparent and smooth

Medium: the bulb surface has a frosted coating

Wide: the surface of the bulb has ridges and facets in the glass

Something to watch out for:

Parcans can burn out heavy (dark or deep-colored) gels quite quickly.