The Collaborative International Dictionary
Ambrotype \Am"bro*type\ (-t[imac]p), n. [Gr. 'a`mbrotos immortal + -type.] (Photog.) A picture taken on a plate of prepared glass, in which the lights are represented in silver, and the shades are produced by a dark background visible through the unsilvered portions of the glass.
Douglas Harper's Etymology Dictionary
1855, American English, apparently from Greek ambrotos "immortal, imperishable" (see ambrosia), with second element from daguerreotype. A type of photograph on glass with lights given by silver and shades by a dark background showing through.\n\nThis invention consists in an improved process of taking photographic pictures upon glass, and also of beautifying and preserving the same, which process I have styled "ambrotype." My improved process has reference to the art of taking pictures photographically on a film of collodion upon the surface of a sheet of glass, the collodion being suitably prepared for the purpose. By the use of the said process, the beauty and permanency of such pictures are greatly increased, and I have on this account styled the process "ambrotype," from the Greek word ambrotos, immortal.
["Specification of the Patent granted to James A. Cutting, of Boston, in the United States of America, Photographer, for an Improved Process of taking Photographic Pictures upon Glass and also of Beautifying and Preserving the same. Dated London, July 26, 1854," printed in "Journal of the Franklin Institute," September 1855]
Wiktionary
n. an early type of photograph in which a glass negative appears positive when displayed on a black background
Wikipedia
The ambrotype (from — “immortal”, and — “impression”) or amphitype, also known as a collodion positive in the UK, is a positive photograph on glass made by a variant of the wet plate collodion process. Like a print on paper, it is viewed by reflected light. Like the daguerreotype, which it replaced, and like the prints produced by a Polaroid camera, each is a unique original that could only be duplicated by using a camera to copy it.
The ambrotype was introduced in the 1850s. During the 1860s it was superseded by the tintype, a similar photograph on thin black-lacquered iron, hard to distinguish from an ambrotype if under glass.
Usage examples of "ambrotype".
I carried, as I marched, an ambrotype in a closed case, which I had obtained deviously.
In sixty-one, any soldier with a dollar and seventy-five cents could have his aspect recorded in the form of ambrotype, tintype, calotype, or daguerreotype.
Ada wished there were a way to capture what she was hearing in the way an ambrotype captures images, so it could be held in reserve for the benefit of a future whose residents might again need access to what it stood for.
There was but one picture--an ambrotype, in an ornate case, of a handsome young man, with that dashing, dare-devil look in his eyes which has ever been attractive to women.
In the ambrotype used as a frontispiece, Whitman was dressed only in his shirt, looking like a farmer just come in from the fields, not an elevated, rarified, idealized creature--a poet--who spoke the language of the gods.
Pangle stood beside him, and theirs was the proud and nervous pose men struck when having ambrotypes made at the start of the war, though instead of rifle musket and Colt pistol and bowie knife, Stobrod and Pangle held fiddle and banjo before them as defining implements.
Rutherford McDowell THEY brought me ambrotypes Of the old pioneers to enlarge.
Compton Mackenzie novels on the shelf, glassy ambrotypes of her late husband Austin night-dusted inside gilded frames up on the mantel where last time Michaelmas daisies greeted and razzled from a little Sevres vase she and Austin found together one Saturday long ago in a Wardour Street shop.
Rutherford McDowell THEY brought me ambrotypes Of the old pioneers to enlarge.