Before the age of photography, around 1839, look for engravings and illustrations.The first successful photographic process was the daguerreotype, developed by Louis Daguerre in 1840 which was in use from around 1841 to the early 1860s.Many local authorities and record offices are loading their collections online.On the back of a Victorian photo at the bottom, there may be some tiny printed writing relating to the Marion company.
Righton, 42 Northbrook Street, Newbury 1903-- (but no Hungerford views after 1909?
The daguerreotype was restricted to the more wealthy and are therefore a fairly rare find.
Other processes followed such as the Ambrotype process invented by Frederick Scott Archer which was in use from the 1850s to about 1890 and was a less a expensive alternative to the daguerreotype.
Edges By the 1880s, cabinet card mounts sometimes had bevelled edges, and were often finished in gold or silver.
Colour The colour of the cardboard mount can also help date the photograph.