A contact print is a photographic print which is made by exposing a sensitized piece of material such as developing paper to light while it is in direct contact with a negative. This was the standard technique used for developing photographs until the enlarger was developed, and it continues to be used today. There are two primary modern uses for contact prints: fine art, and proof sheets. Many beginning photographers learn to make contact prints very early on in their careers, so that they can create proof sheets of their photographs.
To make a contact print, the photographer sets up a light sensitive surface face up under a light source such as an enlarger. Next, the negative is placed directly on top of the sensitized material, and the light is turned on to expose the paper. After a set period of time, the light is turned off, and the paper is developed. Many people use this technique to create a proof or contact sheet of a bunch of negatives, so that they have small versions of the photographs they took to look at, allowing them to decide which pictures to develop.
Obviously, a contact sheet is limited by the size of the negative. In fine art, photographers work with large format negatives which can vary in size. Artists like to make contact prints of large format negatives because of the resulting richness of detail, which can be simply incredible. During the enlarging process, a picture's detail can become distorted or muddy, and a contact print preserves all of the detail perfectly. Large format negatives also perform better during the enlarging process; Ansel Adams, for example, worked with large format cameras to produce his distinctive work.
This principle also applies to digital photography. Digital photographers have probably noticed that the more information they store in a photograph, the more they can play with it. A digital camera with a small megapixel capacity will produce grainy large prints with obscured detail, while more megapixels equals more detail, and a resulting higher print quality.
Making a contact print does require some work. If working with an enlarger as a source of light, the lens will be adjusted and the height of the enlarger head will need to be changed. The photographer also needs to make a test strip, to determine which exposure level would be most suitable for the contact print. Contrast filters and other tools can also be used to change the resulting quality of the finished print. Photographers who have not experimented with large format cameras yet might want to give it a try.