Many characteristics were short lived as new mount designs and features were constantly introduced by the printers to encourage photographers to buy more mounts so as to remain up to date and in fashion.
Whilst a ‘not before’ date can be accurately established for any particular attribute, allowance has been made in the calculations for the fact that some photographers would take longer to use up their stock of card mounts than others.
Miles supplied about 250 pairs of these flintlocks to the state of Virginia in 1800 through 1801 under a military contract. They are extremely rare and if you can find one they run for about ,000. The barrel on that flintlock is 10" and that knife is a good length longer than that with about the sharpest point I have ever seen.
To read more about how the Wizard works, see our free download How the Photo Dating Wizard Works.
The second biggest problem is the emulsion turns dark making the image look dark.
This problem is similar in appearance to when a daguerreotype's silver plate is tarnishing but that (the tarnish) has a bluish tint to it.
An ambrotype (also known as a collodian positive) was an image produced by a type of photographic process first used in the 1850s, succeeding the more expensive daguerreotype, with the image on glass (as opposed to film, paper or metal).
The resulting image is actually a negative, but when viewed against a dark backing (such as black velvet, or a layer of black varnish) or on dark reddish-coloured glass, appears as a positive.