One of the most important items in a darkroom is an enlarger. This piece of equipment is basically a camera in reverse. A camera has the light source in front of the lens and the film behind it and an enlarger has the negative in front of the light and behind the lens. Enlargers are specialized transparency projectors that are used to develop photographic prints from film or glass negatives.
There are two types of enlargers, the condenser enlarger and the diffusion style. The condenser enlargers use condenser lenses to distribute light evenly across the negative, whereas diffusion enlargers use a piece of diffusion glass. Diffusion enlargers typically produce less light through the negative and less contrast. The main advantage of an enlarger is that large prints can be produced from small negatives. Without an enlarger you can only produce a contact print and large images would require large negatives, meaning large cameras. Enlargers can range in price from about $175 to $3,000.