Search billions of records on Ancestry.com
   
 
 
Ambrotypes
Ambrotypes - key facts
 
  1. •Common 1854-1860s.
  2. •The process creates an image on a sheet of glass.  It appears as a negative until a black backing turns the image into a positive.
  3. •More correctly called a ‘wet collodion positive on glass’.
  4. •Usually have their own decorative and protective cases.
  5. •Low contrast—the whites appear as dull grey and detail is less visible in the shadow areas. It can be viewed from all angles.
  6. •In ‘genuine’ (i.e. patented) Ambrotypes, a protective glass was cemented directly to the emulsion side of the original plate, with a Canada balsam resin.
  7. •Less expensive than the daguerreotype
  8. •The Ambrotype was supplanted by the tintype and other processes.
  9. •Ambrotypes were often hand-tinted. Untinted ambrotypes are grayish-white and have less contrast and brilliance than daguerreotypes

Common signs of deterioration
 
  1. •The collodion emulsion may weaken, crack or flake. It may also separate from the glass.
  2. •Decomposing collodion releases gases, such as nitric oxide and nitrogen oxide, which combine with atmospheric moisture to form nitric acid—this attacks the cellulose in the collodion.
  3. •Atmospheric pollutants and residual processing chemicals can cause the collodion image to deteriorate.
  4. •Silver sulphiding will appear as red and green discolouration.
  5. •The glass support can break and glass splinters can scratch the emulsion.
  6. •If the ambrotype is varnished, UV radiation may cause discolouration and yellowing of the varnish.  ‘True’ Ambrotypes show deterioration in the Canada balsam, which darkens and becomes hard over time.
  7. •The painted black backing often flakes off, leaving what appear to be holes in the image.
Examples of Ambrotypes
 
Above:  A beautiful, hand-tinted Ambrotype in protective case. from the 1850s.  Discolouration can be seen around the edges of the image, cause by silver sulfiding and deterioration of the collodion.
Left:  This large Ambrotype was originally in a paper mount inside a frame.  It has been broken across the middle.  The overpainting on this image is extensive and heavy compared to the light tinting on the image above.
Below:  Typical deterioration in Ambrotypes includes cracking of the black backing varnish (left) and sulphiding and abrasion (right).
Right:  This is a ‘true’ Ambrotype.  The completed image was backed with black varnish, then coated on the front with a sticky resin.  A sheet of glass was placed onto this and held in place with paper tape around the edges.
 
On this example you can see evidence of the resin having oozed out (right and bottom edges and top left) and some spotty image deterioration caused by mould growing within the resin (particularly to the left of the face in the highlight area).  These ‘true’ images are much less common than other wet collodion positives on glass.  
 
The yellow areas on the surface of this image are reflections from ceiling lights.