Glossary — Study

The words the trade used, in plain language. Terms here are linked from catalogue entries across the shop.

Albumen print: A paper print made with egg-white binder, the dominant printing process from the 1850s to the 1890s. Glossy surface, warm brownish image tones, highlights often yellowed with age.
Ambrotype: A collodion negative on glass backed with dark material so it reads as a positive. Popular 1854–c. 1865; cased like a daguerreotype but not mirror-like.
Brass mat: The stamped brass frame that sits over a cased image, giving it a finished window. Often carries the photographer's name; its shape and ornament help date the piece.
Cabinet card: A print of about 4¼ × 6½ inches on a card mount, the standard portrait format of the 1870s–1890s. The mount's color, edges, and imprint are dating tools.
Carte de visite (CDV): A small print (about 2½ × 4 in) on card stock, patented in 1854 and especially popular in the 1860s, though the format continued for decades. American examples from 1864–66 may bear a federal tax stamp.
Case (Union case): The hinged, velvet-lined housing for daguerreotypes, ambrotypes, and early tintypes. Early cases are embossed papier-mâché or leather; ornate thermoplastic 'Union' cases date from 1853 on.
Collodion: Guncotton dissolved in ether and alcohol, poured over glass or iron to carry the light-sensitive salts. The wet-plate process that powered ambrotypes, tintypes, and most negatives of 1851–1880s.
Cyanotype: An iron-based photographic process that produces a blue image. Introduced by John Herschel in 1842; later familiar as the blueprint process.
Daguerreotype: The first practical photograph: a unique direct-positive image on silver-plated copper, 1839–c. 1860. Mirror-like; the image flips positive/negative as you tilt it.
Daguerreian: A maker of daguerreotypes — the trade's own word for itself before 'photographer' became standard.
Gelatin silver print: A paper print using silver salts in gelatin, dominant from the 1890s through the 20th century. Neutral black tones; the ancestor of every modern black-and-white print.
Glass dry plate: A gelatin-coated glass negative sold ready to use. Commercially practical by the late 1870s, it freed photographers from coating and developing a wet plate while it was still wet.
Gem tintype: A postage-stamp-sized tintype, made many at a time with a multiplying camera, often mounted in tiny albums or sleeves. Popular 1860s–1880s.
Half plate / sixth plate: Standard plate sizes for cased images. Whole plate 6½ × 8½ in; half 4¼ × 5½; quarter 3¼ × 4¼; sixth 2¾ × 3¼ (the most common); ninth 2 × 2½; sixteenth 1⅜ × 1⅝.
Imprint: The photographer's printed or stamped name and address on a mount or case. The single most useful research thread a photograph can carry.
Mourning / memorial photograph: A portrait made or displayed in remembrance of the dead, sometimes photographed after death. Common and culturally central in the 19th century, not a curiosity.
Monoview (identical duplicate): A stereo-format card made with the same photograph printed twice. It may look like a stereoview, but the two eyes receive no viewpoint difference and therefore no genuine depth.
Negative: The original capture from which paper prints are made — on glass (wet plate, later dry plate) in the 19th century, on flexible film from the 1880s. Daguerreotypes, ambrotypes, and tintypes have no negative; each is one of a kind.
Occupational: A portrait showing the sitter with the tools of their trade — a carpenter with his plane, a typesetter at case. Prized by collectors for what they record of working life.
Preserver: The thin brass foil wrapped around the edge of a cased image's glass-mat-plate sandwich to seal it. Its style helps date the case.
Real photo postcard (RPPC): A photographic print on postcard stock, c. 1903–1930s. Continuous tone under a loupe (no printing dots); the stamp-box pattern helps date the paper.
Recto / verso: Front and back. The verso of a mounted photograph often carries the imprint, inscriptions, or tax stamp that identifies it.
Revenue stamp: A federal tax stamp affixed to taxable American photographs from August 1, 1864, through July 31, 1866, with rare uses just outside that window. A tight piece of dating evidence.
Salted paper print: The earliest paper photograph, 1840s–1850s: matte surface, image in the paper fibers, soft warm detail. Predecessor of the albumen print.
Stereoview (stereograph): A pair of near-identical images mounted side by side, viewed through a stereoscope to give a three-dimensional scene. Mass-produced from the 1850s into the 20th century; the era's home entertainment.
Tintype (ferrotype): A collodion positive on lacquered iron, introduced in 1856 and especially common in the 1860s–70s, with later versions continuing into the 20th century. A magnet can support the identification, but a test through a case can mislead.
Vignette: A portrait style where the image fades softly to nothing at the edges, made by shielding the plate during exposure or printing. Fashionable in several decades; not damage.