Flat-Folding Zograscope

Bill Douglas Cinema Museum^[*] #EXEBD-69025

English? ca. 1760

Dimensions: H= cm, W= cm, D= cm

Lens: ⌀=10.1 cm, ƒ=? cm

 

Figure EXEBD-69025.1 – Flat-Folding Zograscope
Photo © Rod Bantjes.

Figure EXEBD-69025.2 – Closeup of Folding Mechanism
Photo © Rod Bantjes.

This is a biconvex-lens viewer for enhancing the 3D-effect of copper-plate engravings known as vues d'optique. It is an example of an "optical machine " and is included in the Optical Machine Taxonomy.

 

The maker has chosen to do things rather differently from others. The frame lacks the typical turned elements. Also, the bases of zograscopes are usually turned but this one is octagonal with inlaid elements. Here, quite uniquely, the lens folds into the mirror-frame for a completely flat profile. When swung open, the mirror is held in place by thumbscrews of knurled brass and the lens hangs down by gravity. This is an elegant solution that does away with metal hinges and hardware to prop open the mirror –features typical in other designs.

 

The height of the frame is not adjustable, so the maker has set what they considered to be an ideal distance between lens and image (55 cm).

 

For more about zograscopes and their uses and meanings, follow this link.

Endnotes:

^[*] I would like to acknowledge support from the Bill Douglas Cinema Museum in the form of an International Research Stipend. Thanks also to the staff of the Museum for their assistance in the archive.

Contact: rbantjes@stfx.ca