Ambrotype Magnification
Image Structure
Ambrotypes are a photographic process based on the light sensitivity of silver halides. It is a direct positive process and technically a negative. Therefore, the image particles are in the highlights rather than the shadows. Ambrotypes also often have color applied to the image. The color may be very subtle or faded.
Ambrotypes are a photographic process based on the light sensitivity of silver halides. It is a direct positive process and technically a negative. Therefore, the image particles are in the highlights rather than the shadows. Ambrotypes also often have color applied to the image. The color may be very subtle or faded.
What to look for: Under low magnification, the image appears as a continuous tone image. Under high magnification, the very fine image grain will be visible in the highlights. Pigment particles may be visible in hand colored plates.
With 10x magnification (left) and 30x magnification (right), the image appears as continuous in tone.
Under 50x magnification the image grain is clearly visible in the highlights. Pigment particles are visible as well.
Layer Structure
Ambrotypes consist of a polished glass support and image bearing collodion binder. A collodion binder is poured directly onto a polished glass plate, which is backed by a dark material that presents the appearance of a positive image. There is usually a protective varnished applied to the emulsion surface. There is sometimes a cover glass on top or underneath the image-bearing support.
Ambrotypes consist of a polished glass support and image bearing collodion binder. A collodion binder is poured directly onto a polished glass plate, which is backed by a dark material that presents the appearance of a positive image. There is usually a protective varnished applied to the emulsion surface. There is sometimes a cover glass on top or underneath the image-bearing support.
What to look for: An image on a glass support with some type of dark backing (fabric, paint, paper, etc.).
The cross section shows the structure of a typical ambrotype.
This cross section shows the structure of a ruby glass ambrotype.
What to look for: Weeping glass: small droplets or crystalline deposits on either the cover glass or primary support glass. Mold: small organic growths with tendrils on the surface of the emulsion.
Other Characteristics
Ambrotypes can often have color applied to the image. The color may be very subtle or faded.
Ambrotypes can often have color applied to the image. The color may be very subtle or faded.
What to look for: Pigment particles.