by Joelle Steele

In the earliest days of photography (approx. 1837-1848) there was a lot of experimentation with a variety of photographic processes. The time periods in which they were made often overlap. So, you can't simply lump them all together as being the same type of photo from the same era until you learn all the subtle distinctions that make them different and that limit the date or content. Date ranges below are approximate.

Daguerreotypes. Photography (in its earliest form as the Daguerreotype) was not in existence on the American frontier until 1839 at the very earliest — and 1839 is really being overly optimistic that the heavy equipment used in the Daguerreotype process could even have been manufactured and then made it as far as that part of the country at that time in history. Invented 1837, it was in use from 1839-1920s. Popular 1839-58. Always encased and sealed with paper tape. Exquisite, fine, crisp, detailed, high-contrast images. Laterally reversed (unless a reversing mirror was used — which was rare). Mirrored surface. Must be held at an angle to see the image clearly. Earliest ones had a gray or bluish color to them; later ones had a light brown coloration. Both tarnished blue around the edges if air or moisture got inside. Daguerreotypes came in some fairly standard sizes:whole plate 6-1/2" x 8-1/2"; half-plate 4-1/4" x 5-1/2"; quarter-plate 3-1/4" x 4-1/4"; sixth-plate 2-3/4" x 3-1/4"; ninth-plate 2" x 2-1/2"; sixteenth-plate 1-3/8" x 1-5/8"; and double whole 10-1/2" x 13-1/2."

Ambrotypes. Invented 1850. In use 1853-1960s. Popular 1855-1875. Always encased. Laterally reversed image. Image is on glass and needs a dark background behind it, such as black velvet, black varnished metal, black baked-on lacquered cardboard (japanning), or black paint or varnish on the back of the glass itself. Reflective image due to being on glass. Dark, "stormy look," low contrast, grayish appearance, even when hand-tinted. If not encased, hold it up to the light and it will be transparent. Often degraded by time with the black varnish drying, cracking, or peeling, giving it a blistered look. Can also lose its contrast and turn darker with age. Is not mirrored and does not turn blue with age. Image can appear to be destroyed, but can often be restored. Usually in the same sizes as Daguerreotypes. Still in use in the printing industry up to the 1960s.

Tintypes. Invented 1853. In use 1853-1920s. Popular 1855-1890s. Sometimes encased (earlier ones) but more often found in albums. Dark in appearance like an ambrotype, but degree of contrast varies according to who did the processing and how they did it. Image is on iron, not glass (a magnet helps in determining this). Non-reflective surface. Laterally reversed (unless a reversing mirror was used — which was rare). Damage from handling over time appears as crazing and cracking. Very popular during the Civil War, during World War I, and through the 1920s. Often found on cemetery headstones. Usually small in size: 1" x 1-3/8" or 1" x 1/2" ("gemtypes"); 2.5" x 3.5" (most common size); 6-1/2" x 8-1/2" (large size and rare).

Union Cases. Invented 1853. In use 1839-1900. Popular 1839-1870. The earliest images under glass were encased in wooden boxes with brass mats. By 1853, the hinged "union case," made of a thermoplastic resin, was introduced, and many of its numerous manufacturers marked the cases to identify, and therefore to limit, the possible dates of the photos. This doesn't help with every encased photo, since cases could be laying around unused for years and then suddenly have a photo placed in one of them.

This article last updated: 09/11/2014.