Dating old pichtures
Each eye looks at a slightly different image, and the fusion of the two images in the mind creates the illusion of depth. Sizes of stereo cards and slides: The typical mass manufactured stereo card of the period between the Civil War and WW I had a standard dimension: 3 1/2" x 7". The earliest of these cards were made on slightly curved mounts; later cards were made on slightly curved mounts that permitted greater clarity when they were seen in the stereopticon viewer.
A number of photographers, working with larger field cameras, created slightly larger cards of 4" x 7", 4 3/8" x 7" and 4 1/2" x 7".
Flaws that were not obvious in the smaller cards now became very visible. Success in retouching led to innovations in the darkroom and at the camera.
Diffusion of the image reduced the need for retouching. Blue playing card stamps are known to have been used in the summer of 1866 as other stamps were unavailable as the levy came to an end.
These defects are now noticeable in many calotypes, some of which are today little more than pale yellow ghosts. They could be mailed home safely without fear of shattering.
AMBROTYPE (1854 to the end of the Civil War)The ambrotype is a thin negative image on glass made to appear as a positive by showing it against a black background. It couldn't withstand travel or being carried in a locket as a daguerreotype could. The tintype actually does not contain any tin, but is made of thin black iron.
The cost: .00 (more than a weeks pay for most people). Calotypes were never widely popular, and most of those surviving are in museums. In their place, paper folders of the size of the then popular card photographs were used for protection.
The giant spaces they discovered demanded giant cameras.
The camera that documented the famous meeting at Promontory Point, Utah of the tracks of the Central Pacific and Union Pacific railroads on was built to accommodate glass plates 10" x 13".
The camera boated down the Colorado River during the Powell Expedition into the Grand Canyon was 11" x 14".
The work of these photographers, shown in major exhibitions in Washington D.
I found this article on the Internet and thought that some of you who appreciate (and maybe even have a few) old photographs laying around in cardboard boxes or in desk drawers might like to read some tips on ways to try to put a date on when they might have been brass decorative frame.