Aid to identification of the most common black and white historical photographic process and supports

Type of processDate of invention/Introduction (Period of greatest popularity)ImageEmulsion (if any)SupportTypical Presentation: Loose (L), Mounted (M), Case (C), Framed (F), Albums (A)Identification
Daguerrotype1839 (-1850's)Silver and silver/mercury amalgam-Silver coated copper PlateC/FUnique. Negative/positive image in raking light.
Photogenic Drawing1834/1839 (1840's)Silver (POP)-PaperLPaper fibres visible. Sepia - lilac brown.
Salted Paper Print1839 (1840's-1850's)Silver (POP)-PaperL/M/APaper fibres visible. Sepia - reddish brown.
Calotype Print1841 (1840's-1851)Silver (physically developed)-PaperL/M/APaper fibres visible. Sepia, but more contrast than above.
Waxed Paper Calotype Negative1841 (1840's-1851)Silver (physically developed)-PaperLWaxed and traslucent.
Cyanotype1842 (1840's & 1880's-1890's)Iron compounds-PaperL/APaper fibres visible. Blue colour.
Wet Collodion Negative1851 (-1870's)Silver (physically developed)CollodionGlassLHand-coated, fingermarks in emulsion and varnish at corners of plate. May be creamy colour in dark areas.
Collodion Positive1852 (-1880's)Silver (physically developed)CollodionGlassL/FUnique. No negative/positive image in raking light. Black backing or ruby glass.
Tintype1856 (-1930's)Silver (physically developed)CollodionIronL/C/F/A (Card folders)Cased tintypes - test with magnets over cover glass - magnetic field.
Albumen1850 (-1890's)Silver (POP)AlbumenPaperL/M/F/AUsually finely crazed emulsion. Yellowish sepia. Thin paper base. Tendency to curl.
Collodio-Chloride1864 (1880's-1910's)Silver (POP)CollodionPaperL/M/F/AAppears like gelatine POP.
Platinum1873 (1879-1914)PlatinumPaperL/M/F/APaper fibres visible. Degraded transfer image on facing paper. Little image fading.
Gum bichromate1856 (1890's-1920's)PigmentGum arabicPaperL/M/F/AMay be glossier in darker areas. May be slight relief in image. Pigment particles visible under low magnification. Pigment colour.
Carbon print1855/64 (1868-1940's)PigmentGelatinPaperL/M/F/AMay be glossier in darker areas. More pronounced relief image. Little image fading. Pigment colour.
Gelatin dry plate negative1871/73 (-1930's)Silver (chemically developed)GelatinGlassLUsually non-image strip near border. Smooth, even, thin coating.
Silver gelatin fibre/ paper based prints1882 (-1960's) (POP)
1873 (-1960's) (DOP)
Silver (POP & DOP)GelatinPaperL/M/F/ASometimes very pronounced mirror tarnish for DOP.
Cellulose nitrate1889 (-1950)Silver (chemically developed)GelatinCellulose nitrateL/Plastic or paper walletsSometimes edge printed "CELLULOSE NITRATE"
Cellulose acetateLate 1920's (to present)Silver (chemically developed)GelatinCellulose acetateL/Plastic or paper walletsSometimes edge printed "SAFETY"
Polyester1940's/50's (to present)Silver (chemically developed)GelatinPolyesterL/Plastic or paper walletsNot usually edge printed.
Resin-coated paper1972 (to present)Silver (chemically developed)GelatinPolyethylene coated paperL/M/F/ATends to lie flat. More plastic than plain paper supports.

POP = printed out print. This means that the sensitised printing paper is exposed, in contact with a negative, to light (usually daylight) until the final image appears. The printing paper is then fixed and washed. There is no development stage. They are usually sepia in colour. 

Physically developed  images use silver ions from the developer which are deposited on the silver of the latent image. The silver does not usually come from the photographic emulsion itself, unless it has been dissolved in the developer solution first.

DOP = developed out prints. In this case the sensitised printing paper is exposed, (usually under an enlarger) to artificial light for a shorter period of time than POP. This produces a latent image which is not visible to the human eye. The printing paper is then placed in a developer until the image appears. The silver in the image comes from the sensitised paper itself. After this, the printing paper is placed in a stop bath, fixed and washed. It is much quicker to produce than POP and the process is more controlled and the results more predictable.

Table "Aid to identification of the most common black and white historical photographic processes and supports" from page 4 of The British Library, Preservation Advisory Centre - Photographic material.