A blueprint copier is a copier that takes on the really large jobs regular copiers cannot, such as blueprints. A blueprint copier can be used to expose pin graphics and to draft overlays. It can also be used for light sensitive screens, film negatives or positives, and sepia prints.

A blueprint copier uses a vacuum system to ensure full contact with the item being copied. This is important because it can be difficult to keep larger copies still as they feed through the blueprint copier. If the original does not stay still, the copy will be blurred.

It is also possible to acquire a blueprint copier that doubles as a light table and has a preview top. A blueprint copier can also sit on a self-contained stand. This type of blueprint copier is made only for exposing media and requires a separate developing system.

A blueprint copier handles a wide range of light-sensitive materials. Therefore, there are several different types of blueprint copiers, with most using eighteen fluorescent lamps at 65 watts each for exposures. They also generally contain four cool white lamps at 40 watts each for operation of the light table. A blueprint copier also has a power switch and mode switch, and a timer to control exposure time and heat distribution.

Above all, a blueprint copier is made to deal with blueprints. Blueprints are the standard way to copy large construction and architectural drawings. These large pieces of paper with the house design on them are called blueprints because they have white lines on a blue background. More recent versions of the process, however, use blue lines on a white background. The term blueprint can be used to describe two printing methods: the blueprint and the diazotype.

The process of blueprinting was invented in 1842. A design to be copied is first drawn onto translucent paper. It is then placed against paper that has been sensitized with ferric ammonium citrate and potassium ferricyanide, which is then exposed to light. The areas on the sensitized paper that are not covered by the drawing are changed to blue as the light causes a chemical reaction between the two chemicals. In order to copy these specialized prints, it is necessary to use a blueprint copier.