It is known that mirrors are not an uncommon photographic tool; however, their ability for creating unusual and highly effective visual statements is often indicated, while their use is not explored properly in photography classes.
Just experiment with mirrors in photography. Mirrors can be used as distortion producing devices or as sources for multiple images. Currently, probably the best known device is the kaleidoscope. Simply place a camera on a copy stand, aim it at a live subject or use the device in the enlarger.
Typically the final result greatly depends on the quality of the mirrors. Nevertheless, you can use even standard mirrors, especially for introductory experiments.
A mirror can be coated with silver or aluminum either on the front or rear. Most household mirrors are coated on the rear; however, the best mirrors are those coated with the metal on the front. In normal environment the fairly delicate metal coating may be exposed to bumps and scratches; that is the reason for coating the rear side of the mirror. However, weak secondary reflection from the front glass surface is one of the great disadvantages of such mirrors.
You won't have this problem with the first surface mirrors but you have to handle them with care, though. There are numerous sources where you can get such mirrors; the one that is usually recommended is Edmund Scientific Company located in Barrington, NJ. Probably the minimum size for use in front of a camera is something like 4X5 inches. If possible, use something a little smaller within a 2 1/4 x 3 1/4 or larger enlarger.
You can obtain interesting results even with a single mirror. Place the mirror just below the edge of the lens and photograph the reflection of a scene in the mirror and the subject itself. An "instant" reflecting lake is then created where originally none was. Particularly, this often impacts architectural scenes.
You can use two mirrors joined along one edge and make interesting fractured kaleidoscopic juxtapositions of mundane objects with a single exposure. You can also vary the angle between the mirrors to alter the number and orientation of the multiple images. The composition can be also altered by changing the direction in which the camera is aimed within the mirrored "V" formed by the mirrors.
SLR type cameras are the best choice cameras for manipulations of this kind. However, while built-in meters are most useful at all times, auto focusing may or may not be such depending on situation. The edges of the mirror will be affected by the delineation of the mirror edges. Thus, the final visual quality of the image will be as well. That is why it is advisable to use the lens in stop-down mode, not at full viewing aperture.
To prevent accidental contact between the mirrors and the glass of the lens make sure the lens is protected with a clear protective or UV filter when working with these mirrors near a camera.
The renowned newspaper photographer Arthur Fellig, better known as Weegee, used to place mirrors inside of the lens cone of enlargers. However, you need to remember that there is a risk of dropping a mirror on the rear surface of the enlarger lens. So you need to take a great care while placing mirrors within an enlarger lens cone in this fashion. You can also place a protective filter over the rear of the lens's rear element to avoid problems.
These reflections are those of portions of negatives placed on the film carrier of the enlarger. Truly startling and unplausible results can be produced by kaleidoscopic mirror arrangements or just one simple mirror.