Dating Portraits - Vignetted Head

The vignetted head type of portrait focuses on a person's most important attribute available to the camera, the face. These usually are cut off just below the shoulder, giving the classical "bust" image. Darrah observed that the size of the image of the person's head increased over time.

Dating:

Small image, 20mm x 20mm or less - 1860-64

Image 20 to 30mm x 25 to 40mm - 1860-67

Image larger than 30mm x 40mm - 1866-75

Large head, covering 3/4 of print (typically 50mm x 75mm) - 1874-90

Observations:

While early images tend to be smaller, it seems to me that later images can also sometimes be small, though the larger sizes are more common. This area needs further study.