An enlarger is a projection device used to produce photographic prints. It can be used to print a negative image on photographic paper. The image itself can be enlarged or reduced within acceptable limits. Enlargers can be stationary or folding. There are also special portable enlargers.

Even though most enlargers could use camera lenses, special lenses were designed for them. This was done because an enlarger did not require an infinity focus, and even using a lens of lower quality allowed it to achieve high-quality photographic prints (which was not the case with a camera). Enlarger lenses used an iris diaphragm, which helped increase the depth of field and adjust the exposure when printing. The letter U was added to the name of a lens model, for example, Industar-96U, or just I-96U.

The history of the development of Soviet enlargers is replete with mysteries and riddles. The truth is that the shortage of many appliances prompted Soviet amateur photographers to make their own. For example, the Soviet Modelist-Konstruktor magazine described how to make an enlarger using the most common water can. Those who took the matter seriously consulted the book called “Homemade Enlargers”.

The 1936 issue of the Sovetskoye Foto magazine describes one of the first Soviet enlargers, “The Arfo enlarger is based on the latest European enlargers. The device consists of a vertical 1.1-meter-high column equipped with a cylindrical head that has a spherical dome, and a baseboard to project the image onto. The device also features a condenser with a diameter of 150 mm and a lamp with a power of 150 watts, designed for a voltage of 127 volts.” This enlarger could make 40 by 50 cm prints.

In 1946, soon after the war ended, the Moscow KoopLaborKhirurgia Production Artel, Krasnogorsk Mechanical Plant and Kharkiv FED plant set up production of U-2 photo enlargers. Later, this model was produced by the Novosibirsk Instrument-Building Plant and the Photo Accessories Plant, which was supervised by the Moscow City Executive Committee. U-2 is a desk small-format vertical enlarger with a two-lens condenser and ground glass.