The stereoscopic image above is of the Mule Deer Group at the American Museum of Natural History in the hall of American Mammals. The 3D view helps you see the junction between the 3D foreground and the painted background (by J.P.Wilson). I received an e-mail form Michael Anderson at the Yale Peabody Museum with whom I had worked on previous projects (see for example the posts on the Cold Bog Camera) reminding me of an e-mail I had sent regarding a photograph of J.P.Wilson working on the diorama. In the foreground is the survey material that includes his painting (for colour accuracy) and panoramic assembly of photographs (under normal circumstances for geometric projection). What is strange about this example is that it is the painting, not the photograph that is gridded for transfer onto Wilson’s diorama shell grid (see detail below).
The question on Michael’s mind was if Wilson was using his developed projection technique by this time, and if so why was he working with a grid on the painting. To try to answer this question I built two dioramascopes that would test the projection of the grid on the painting onto a scale model of the diorama shell (that would be lined with photographic paper). One would test the grid as a Hauck picture plane (as a circular picture plane as in Wilson’s technique) and one as a flat picture plane as described in an article by F. L Jaques, a contemporary of Wilson’s.
A tiny light bulb is located at the ideal viewing position and the grid is placed in the correct scale location so that the centre of the grid corresponds to the projection on the diorama shell to the correct height. The two grids cast a shadow on the photographic paper (located at the scale position of the diorama shell). As you can see, the grid shadow from the circular picture plane fills the diorama shell to the correct extent while the flat picture plane grid falls well short. the grid on the dioramascope with the circular picture plane has the horizon cut in it (in the correct grid squares) and these land in the same position as the horizon in the diorama. (See flattened out prints below). It therefore seems that Wilson was using his fully developed projection technique for this diorama, but that he chose to work from the painting rather than the photographs. Why would he do this? If you look carefully, the painting is made from a slightly different position from the photograph, and perhaps on his return he decided that this viewing position would work better for the diorama.
The top print is the print from the flat picture plane and the one below uses the Wilson method. Both to the same scale. In both the paper extends beyond the edge of the diorama but in the lower print the grid fills the diorama shell whereas the upper print using the flat picture plane falls short.