Tabular-grain film is a type of

photographic film Photographic film is a strip or sheet of transparent film base coated on one side with a gelatin emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of the crystals determine ...

that includes nearly all color films, and many black and white films like

T-MAX T-Max (), stylized T-MAX or T.max, was a South Korean pop music group formed in 2007 under the label 2Step Entertainment (later Planet 905). The group began as a trio, where the "T" in its name was derived from the words "triple" and "trinity". ...

films from

Kodak The Eastman Kodak Company (referred to simply as Kodak ) is an American public company that produces various products related to its historic basis in analogue photography. The company is headquartered in Rochester, New York, and is incorpor ...

(with Kodak's T-grain emulsion), Delta films from

Ilford Photo Harman Technology, trading as Ilford Photo, is a UK-based manufacturer of photographic materials known worldwide for its ILFORD branded black-and-white film, papers and chemicals. Historically it also published the '' Ilford Manual of Photograp ...

and the

Fujifilm , trading as Fujifilm, or simply Fuji, is a Japanese multinational conglomerate headquartered in Tokyo, Japan, operating in the realms of photography, optics, office and medical electronics, biotechnology, and chemicals. The offerings from the ...

Neopan Neopan was originally a family of black-and-white films from Japanese manufacturer Fujifilm for both professional and amateur use. The range now only comprises one film; Neopan ACROS 100 II, a traditional silver halide black and white film ...

films. The

silver halide A silver halide (or silver salt) is one of the chemical compounds that can form between the Chemical element, element silver (Ag) and one of the halogens. In particular, bromine (Br), chlorine (Cl), iodine (I) and fluorine (F) may each combine wi ...

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macro ...

s in the film

emulsion An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Alth ...

are flatter and more '' tabular'' (hence T-Grain).

Tabular crystals

panchromatic Panchromatic emulsion is a type of black-and-white photographic emulsion that is sensitive to all wavelengths of visible light. Description A panchromatic emulsion renders a realistic reproduction of a scene as it appears to the human eye, altho ...

emulsions, the sensitivity of the

crystal is enhanced by sensitizing dyes that

adsorb Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the ''adsorbate'' on the surface of the ''adsorbent''. This process differs from absorption, in which a f ...

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. 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 took until roughly 1970 for emulsion engineers to be able to make emulsions that consisted mainly of tabular crystals. Moreover, it was not until the 1980s 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 law In mathematics, a reciprocity law is a generalization of the law of quadratic reciprocity to arbitrary monic irreducible polynomials f(x) with integer coefficients. Recall that first reciprocity law, quadratic reciprocity, determines when an irr ...

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 to be 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 fixer.

Tabular crystals

Fixing tabular crystals

References

Further reading