Photographic grey

The first of the Midland Railway 990 Class locomotives painted in photographic grey in 1908
Side-view builder's photo of a South Australian Railways narrow-gauge T class locomotive painted photographic grey in 1903
A 94 class locomotive of the Cambrian Railways painted in two shades of photographic grey to further pick out detail and with a variation on the company's livery.

Photographic grey, also known as works grey, was a paint scheme commonly applied to steam locomotives during the period before colour photography became commonplace. It was applied to allow sharper, more detailed images of the locomotive to be recorded. The first photographs of railways and their locomotives were made by private individuals, but by the 1860s the railway companies themselves were keen to create official photographs of the highest quality possible of their latest designs, which led to the adoption of photographic grey in railway photography.