George Washington Wilson & Co. photographic collection The George Washington Wilson and Co. photographic collection consists of over 40,000 glass plate negatives, produced by the Aberdeen firm between the second half of the nineteenth century and the early twentieth century. Please note that it is very difficult to date images due to the fact that: • there are no extant company administrative papers • each glass plate negative size (Stereoscopic, Imperial, and Cabinet) had a separate numbering system • when the company introduced dry gelatine plates the numbering system for all of the types of plate size were given the same cataloguing number, superseding the previous system • popular views were often re-photographed to keep the image up-to-date, but the image retained its original number, so two plates with the same number can show the view of a location from different years, often decades apart • some early plates were cut down to create different print sizes, the plate was then given a new number, so the same exact view can exist with two different numbers. Rough Dating system: • Plates numbered 2000 – 6000 are usually from the early to mid-1880s • Plates numbered 7000 – 8000 are usually from the mid-1880s • Plates numbered in the 9000s or the 20,000s are from the late 1890s • Plates numbered 10,000 – 13,000 are usually later than 1890s • Plates numbered 14,000 – 15,000 are usually c.1900 – 1907 • Plates numbered in the 21,000 are usually c. 1900. c 1850 - early 20th century