Tabular-grain film is a type of
photographic filmPhotographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variable crystal sizes that determine the sensitivity, contrast and resolution of the film...
that includes nearly all color-films,
T-MAXKodak Professional T-MAX Film is a continuous tone, panchromatic, tabular-grain black and white negative film made by Eastman Kodak. It is sold in three speeds: 100, 400 and 3200...
films from Kodak (with Kodak's
T-grain emulsion),
DeltaIlford Delta is a series of photographic films manufactured by Harman Technology Limited. Delta films are tabular-grain black-and-white films.....
films from
Ilford PhotoIlford Photo is a manufacturer of photographic materials known worldwide for its black-and-white film and papers and chemicals, as well as its range of Ilfochrome and Ilfocolor colour printing materials. Ilfochrome was formerly called Cibachrome, developed in partnership with Swiss company CIBA-Geigy...
and the
Fujifilmis a Japanese company known for its photographic film and cameras. Fujifilm is the world’s largest photographic and imaging company. Fuji operates 223 subsidiary companies for research, manufacture and distribution of products, with manufacturing facilities in Asia, Europe, and the United States of...
Neopan films. The
silver halideA silver halide is one of the compounds formed between silver and one of the halogens — silver bromide , chloride , iodide , and two forms of silver fluorides. As a group, they are often referred to as the silver halides, and are often given the pseudo-chemical notation AgX...
crystalA crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is crystallography...
s in the film
emulsionPhotographic emulsion is a layer of light-sensitive material coated onto a substrate. In Silver-gelatin photography, the emulsion consists of silver halide crystals suspended in gelatin, and the substrate may be glass, plastic film, paper or fabric....
are flatter and more
tabular (hence T-Grain).
In
panchromaticPanchromatic film is a type of black-and-white photographic film that is sensitive to all wavelengths of visible light. A panchromatic film therefore produces a realistic image of a scene. Almost all modern photographic film is panchromatic, but some types are orthochromatic and are not sensitive...
emulsions, the sensitivity of the
silver halideA silver halide is one of the compounds formed between silver and one of the halogens — silver bromide , chloride , iodide , and two forms of silver fluorides. As a group, they are often referred to as the silver halides, and are often given the pseudo-chemical notation AgX...
crystal is enhanced by sensitizing dyes that adsorb on the crystal surface.
Tabular-grain film is a type of
photographic filmPhotographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variable crystal sizes that determine the sensitivity, contrast and resolution of the film...
that includes nearly all color-films,
T-MAXKodak Professional T-MAX Film is a continuous tone, panchromatic, tabular-grain black and white negative film made by Eastman Kodak. It is sold in three speeds: 100, 400 and 3200...
films from Kodak (with Kodak's
T-grain emulsion),
DeltaIlford Delta is a series of photographic films manufactured by Harman Technology Limited. Delta films are tabular-grain black-and-white films.....
films from
Ilford PhotoIlford Photo is a manufacturer of photographic materials known worldwide for its black-and-white film and papers and chemicals, as well as its range of Ilfochrome and Ilfocolor colour printing materials. Ilfochrome was formerly called Cibachrome, developed in partnership with Swiss company CIBA-Geigy...
and the
Fujifilmis a Japanese company known for its photographic film and cameras. Fujifilm is the world’s largest photographic and imaging company. Fuji operates 223 subsidiary companies for research, manufacture and distribution of products, with manufacturing facilities in Asia, Europe, and the United States of...
Neopan films. The
silver halideA silver halide is one of the compounds formed between silver and one of the halogens — silver bromide , chloride , iodide , and two forms of silver fluorides. As a group, they are often referred to as the silver halides, and are often given the pseudo-chemical notation AgX...
crystalA crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is crystallography...
s in the film
emulsionPhotographic emulsion is a layer of light-sensitive material coated onto a substrate. In Silver-gelatin photography, the emulsion consists of silver halide crystals suspended in gelatin, and the substrate may be glass, plastic film, paper or fabric....
are flatter and more
tabular (hence T-Grain).
Tabular crystals
In
panchromaticPanchromatic film is a type of black-and-white photographic film that is sensitive to all wavelengths of visible light. A panchromatic film therefore produces a realistic image of a scene. Almost all modern photographic film is panchromatic, but some types are orthochromatic and are not sensitive...
emulsions, the sensitivity of the
silver halideA silver halide is one of the compounds formed between silver and one of the halogens — silver bromide , chloride , iodide , and two forms of silver fluorides. As a group, they are often referred to as the silver halides, and are often given the pseudo-chemical notation AgX...
crystal is enhanced by sensitizing dyes that adsorb on the crystal surface. Therefore, sensitivity can be increased by adsorbing more sensitizing dye. This requires increasing the surface area of the crystal, and also improving the dye molecules to form a dense assembly of the dye molecules. Tabular grain emulsion solves the first part of this problem.
Tabular crystals tend to lie along the film's surface when coated and dried. This reduces scattering of light and increases resolution.
Tabular crystals usually have two twinned planes parallel to each other. They are formed at the very beginning of the crystallization. The crystal tends to grow at the edges and not on the main planes, forming very thin crystals of very large surface areas. Tabular crystals probably existed from very early days of silver-gelatin photography. However, it was about 1970 when emulsion engineers could make emulsions that consisted mainly of tabular crystals. Moreover, it was not until the 1980's that tabular crystals began to be used in production emulsions.
Tabular grain technology brought significant improvements to the image quality of the film, particularly in the improvement of resolution and granularity. However, several more key technologies were implemented into tabular grain products. Many of these concurrent improvements were applied to non-tabular grain products to improve image quality. Therefore, when tabular grain technology is described by uninformed writers, its advantage tends to be overemphasized. For example, excellent
reciprocity lawIn photography and holography, reciprocity refers to the inverse relationship between the intensity and duration of light that determines the reaction of light-sensitive material. Within a normal exposure range for film stock, for example, the reciprocity law states that the film response will be...
is not an inherent property of tabular crystals but rather the result of other techniques introduced at about the same time.
Fixing tabular crystals
Tabular crystals grow along the edges and not on the main planes. Similarly, tabular crystals dissolve mainly along the edges and this causes the crystals more difficult and slow to fix in the fixing stage. Users of tabular grain films are advised to ensure sufficient fixing time, at least twice the clearing time in rapid
fixerPhotographic fixer is a chemical used in the final step in the photographic processing of film or paper. The fixer stabilises the image, removing the unexposed silver halide remaining on the Photographic film or photographic paper, leaving behind the reduced metallic silver that forms the image,...
.