There are a swarm of reproduction tintypes, ambrotypes, daguerreotypes and CDV's on the market. These range all the way from the unnoted soldier all the way up to famous persons such as R.E. Lee, Jesse James, U.S. Grant, etc.
A good way to tell these reproductions is from the dot matrix pattern that modern printers employ. BE SURE to obtain a magnifying glass or loupe and look for this!!! But with technology becoming better and better each day, it is getting harder to tell.
This particular tintype of Lee was brought to me from a fellow that came to my table at a local relic & gun show. He wanted my opinion. It didn't take long to disappoint him on his recent purchase. Although saddened by the news, he later allowed me to scan the image for research purposes.
This particular tintype is of the decal type. A decal like image is placed upon a tin plated sheet. Tell tale signs include, trapped air bubbles beneath the image. In some cases, a NEW chemical smell is present from the image. Also, a white fixative is used on many of these. If possible to remove the tintype from the case, then look for a white film between the metal and the image. If you see this, then steer clear!!
These tintypes, etc are then enclosed in an original matte and tintype case. Looks pretty good from a distance, but close examination will tell. These are all over the market!!