ambrotype
Ferrotypes, or tintypes
Ambrotype, from the Selected Civil War photographs, 1861-1865 (Library of Congress)
© Library of Congress, Prints & Photographs Division, [reproduction number, LC-B8184-10038 DLC]
The ambrotype (1851-1890s) is a thin negative image on glass made to
appear as a positive by showing it against a black background. The reverse of
the glass plate was either painted black or backed with a black material. The
ambrotype was an inexpensive alternative to the daguerreotype, similar in size
and also mainly used for portraits. Just like daguerreotypes they were kept in
wooden or leather cases and were unique images. But ambrotypes were not so
expensive and easier to produce, although their exposure time was much longer.
It was not uncommon for an ambrotype to be coloured, if not coloured they have a
grayish white appearance.
Ferrotypes, or tintypes (1865-late 1890s) (they
actually didn't contain any tin) are processed on thin iron plates. Ferrotypes
like ambrotypes are actually negative images, but on a dark background they look
like positives. The emulsion is put on a thin sheet of iron and coated with
black or dark brown lacquer or enamel. Like daguerreotypes and ambrotypes the
images are unique and were almost always used for portraits. Ferrotypes remained
popular for more than half a century because of their durability, ease of
production, and comparatively low cost. When coloured, ferrotypes were often
varnished to protect the colour dyes. Ferrotypes are best stored in dry and
closed cassettes.
The ferrotypes on this page still look very sharp. Although very dirty they
have not blackened as most of these photographs tend to do.
The photograph below has been coloured in by hand, which is only slightly
visible in the woman's face. At the bottom of the photograph a black area is
visible. A very close look at the photograph also reveals something like thin
threads and twisted lines under the photographs surface. This is corrosion of
the support, caused by too much humidity and by oxidation. Like most portraits
this one is also mounted on paper. The outlines of the passe-partout are clearly
visible, as well as acidic stains (the brown spots). On the image back of the
image you can see the the plate of tin under the torn paper layer and oxidated
textile which is glued to the passe-partout.
