Hello All, found this on another list and thought it was pretty interesting. Dottie "Dating Photographs" Daguerrotypes were silver-clad copper sheets mounted behind glass and encased in a hinged leatherette case. They were popular from 1840 to 1870, approx., although I don't think they saw widespread use in this country until the mid- to late-1850s. Ferrotypes (true tin types) were evident in this country from 1856 until World War II or even later. After 1870 some tintypes have a chocolate or brownish tint and many employ painted backdrops and fake props. Pre-1870 tintypes will have a plain backdrop. Tiny tintype portraits -- 7/8 by one inch -- were popular from 1863 to 1890. Carnival tintypes - traveling photographers were in use from 1875 until the 1940s. These photos often have painted backdrops such as Niagra Falls, beach scenes, novelty props or comic set ups. Cabinet or studio cards - paper prints mounted on cardboard stock came around in the post-Civil War era. I believe they became most popular in the post-1880 period. The best way to try and date photos is by clothing styles. Experts can tell the difference, it all looks the same to me.