Stereoscopic images, sometimes erroneously called 3D images, aren’t an entirely modern idea: stereo picture cards and viewers were very popular in Victorian and Edwardian times, allowing people at home to view locations in Britain, as well as more exotic places abroad. The most common format was a card roughly 175 mm wide and 90 mm high, as shown below, with the centres of two separately-photographed images centred around 70mm apart, close to the spacing of human eyes, and viewed by means of a simple hand-held viewer.
The images provided here are mainly of this format.
To see the full stereo effect, the viewing size and distance requires careful adjustment. In order of preference, stereo pictures can be viewed by:
Note that different types of viewer have different centre spacings for each eye. The spacing of human eyes ranges between 54 and 74 mm, with an average of 62 mm, so the suitability of a particular viewer may vary with the individual concerned. Victorian viewers typically have a spacing of 55 mm, perhaps more suited to the people of that age, whilst modern viewers, such as the prismatic viewer mentioned above, later metal viewers, the VistaScreen 3D Viewer and View-Master range all have a spacing of around 65 mm, which is close to the average. The Lite Owl 3D-Viewer, on the other hand, is nearer to 80 mm, as it's intended to be used at a varying distance from the user’s eyes.
©Ray White 2020