The Local History department of Dundee City Council has a number of Stereoscopic Holmes Cards taken in and around Dundee. Some are dated to the 19th century, while others are of unknown date. As the photographs are mounted on backing cards for filing purposes, they would be impossible to view with a traditional Holmes viewer, even if one were available.
To make the Holmes cards suitable for 3D viewing, they have been scanned, brightened and sharpened using a graphics package. They were then processed using a commercial piece of software into single red/cyan separated single images that could be viewed with easily available red/cyan 3D glasses. This technique is known as the ‘Anaglyph’ or ‘Anachrome’ method.
The idea is to provide images that look fairly normal without glasses as 2D images for inclusion in websites. Care is taken to adjust for a better overlay fit of the two images, which are layered one on top of another. Only a few pixels of non-registration give the depth cues required for 3D.