In panchromatic emulsions, the sensitivity of the silver halide 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. 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 is not an inherent property of tabular crystals but rather the result of other techniques introduced at about the same time.
Fixing tabular crystalsedit
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.
Referencesedit
Further readingedit
Kofron, J.T.; Booms, R.E. (1986). "KODAK T-Grain Emulsions in Color Films". Journal of the Society of Photographic Science and Technology of Japan. 49 (6): 499–504. doi:10.11454/photogrst1964.49.499.
(PDF). Publication No. H-1: EASTMAN Professional Motion Picture Films. Eastman Kodak. pp. 23–27. Archived from the original (PDF) on September 30, 2012.
George L. Smyth. (PDF). Handmade Photographic Images. Archived from the original on September 30, 2012.
January 01, 1970
tabular, grain, film, this, article, includes, list, references, related, reading, external, links, sources, remain, unclear, because, lacks, inline, citations, please, help, improve, this, article, introducing, more, precise, citations, april, 2012, learn, wh. This article includes a list of references related reading or external links but its sources remain unclear because it lacks inline citations Please help improve this article by introducing more precise citations April 2012 Learn how and when to remove this message Tabular grain film is a type of photographic film that includes nearly all color films and many black and white films like T MAX films from Kodak with Kodak s T grain emulsion Delta films from Ilford Photo and the Fujifilm Neopan films The silver halide crystals in the film emulsion are flatter and more tabular hence T Grain Contents 1 Tabular crystals 2 Fixing tabular crystals 3 References 4 Further readingTabular crystals editIn panchromatic emulsions the sensitivity of the silver halide 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 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 is not an inherent property of tabular crystals but rather the result of other techniques introduced at about the same time Fixing tabular crystals editTabular 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 References editFurther reading editKofron J T Booms R E 1986 KODAK T Grain Emulsions in Color Films Journal of the Society of Photographic Science and Technology of Japan 49 6 499 504 doi 10 11454 photogrst1964 49 499 KODAK T Grain Emulsions PDF Publication No H 1 EASTMAN Professional Motion Picture Films Eastman Kodak pp 23 27 Archived from the original PDF on September 30 2012 George L Smyth Chris Johnson s Film Development Information PDF Handmade Photographic Images Archived from the original on September 30 2012 Retrieved from https en wikipedia org w index php title Tabular grain film amp oldid 1181934008, wikipedia, wiki, book, books, library,
