RA-4 Process
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RA-4 Process
RA-4 is Kodak's proprietary name for the chemical process most commonly used to make color photographic prints. It is used for both minilab wet silver halide digital printers of the types most common today in photo labs and drug stores, and for prints made with older-type optical enlargers and manual processing. More specifically, common color photographic paper is carefully exposed to form a latent image of the picture, and then the paper is run through the series of chemicals that together comprise the RA-4 process to convert the latent image into the final print. RA-4 uses Color Developing Agent 3, in combination with color couplers in the emulsion to generate color dyes. RA-4 is a standardized chromogenic process used worldwide to make prints with a variety of equipment, photographic paper, and chemicals. Kodak created the RA-4 process for its color negative photographic papers. Fujifilm, Fuji, [ Agfa, and other present and past photographic supply companies also make or have ...
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Eastman 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 incorporated in New Jersey. Kodak provides packaging, functional printing, graphic communications, and professional services for businesses around the world. Its main business segments are Print Systems, Enterprise Inkjet Systems, Micro 3D Printing and Packaging, Software and Solutions, and Consumer and Film. It is best known for photographic film products. Kodak was founded by George Eastman and Henry A. Strong on May 23, 1892. During most of the 20th century, Kodak held a dominant position in photographic film. The company's ubiquity was such that its " Kodak moment" tagline entered the common lexicon to describe a personal event that deserved to be recorded for posterity. Kodak began to struggle financially in the late 1990s, as a result of the ...
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Minilab
A minilab is a small photographic developing and printing system or machine, as opposed to large centralized photo developing labs. Many retail stores use film or digital minilabs to provide on-site photo finishing services. With the increase in popularity of digital photography, the demand for film development has decreased. This means that the larger labs capable of processing 30,000-40,000 films a day are going out of business, and more retailers are installing minilabs. In Kodak and Agfa minilabs, films are processed using C41b chemistry and the paper is processed using RA-4. With these chemical processes, films can be ready for collection in as little as 20 minutes, depending on the machine capabilities and the operator. A typical minilab consists of two machines, a film processor and a paper printer/processor. In some installations, these two components are integrated into a single machine. In addition, some digital minilabs are also equipped with photo-ordering kiosks. ...
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Photographic Paper
Photographic paper is a paper coated with a light-sensitive chemical formula, like photographic film, used for making photographic prints. When photographic paper is exposed to light, it captures a latent image that is then developed to form a visible image; with most papers the image density from exposure can be sufficient to not require further development, aside from fixing and clearing, though latent exposure is also usually present. The light-sensitive layer of the paper is called the emulsion. The most common chemistry was based on silver halide (the focus of this page) but other alternatives have also been used. The print image is traditionally produced by interposing a photographic negative between the light source and the paper, either by direct contact with a large negative (forming a contact print) or by projecting the shadow of the negative onto the paper (producing an enlargement). The initial light exposure is carefully controlled to produce a gray scale image on th ...
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Latent Image
{{citations needed, date=November 2015 A latent image is an invisible image produced by the exposure to light of a photosensitive material such as photographic film. When photographic film is developed, the area that was exposed darkens and forms a visible image. In the early days of photography, the nature of the invisible change in the silver halide crystals of the film's emulsion coating was unknown, so the image was said to be "latent" until the film was treated with photographic developer. In more physical terms, a latent image is a small cluster of metallic silver atoms formed in or on a silver halide crystal due to reduction of interstitial silver ions by photoelectrons (a photolytic silver cluster). If intense exposure continues, such photolytic silver clusters grow to visible sizes. This is called ''printing out'' the image. On the other hand, the formation of a visible image by the action of photographic developer is called ''developing out'' the image. The size of ...
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Color Developing Agent 3
The third in the series of color developing agents used in developing color films, commonly known as CD-3, is chemically known as N- -[(4-Amino-3-methylphenyl)ethylaminothyl">4-Amino-3-methylphenyl)ethylamino.html" ;"title="-[(4-Amino-3-methylphenyl)ethylamino">-[(4-Amino-3-methylphenyl)ethylaminothylethanesulfonamide Sesquisulfate Monohydrate. In color development, after reducing a silver atom in a silver halide crystal, the oxidized developing agent Chemical reaction, combines with a color coupler to form a color dye molecule. CD-3 is used in many processes including VNF-1 and the E-6 process. See Also * Color Developing Agent 1 * Color Developing Agent 2 * Color Developing Agent 4 The fourth in the series of color developing agents used in developing Color photography, color films, commonly known as CD-4, is chemically known as 4-(N-Ethyl-N-2-hydroxyethyl)-2-methylphenylenediamine sulfate. In color development, after reduci ... References {{organic-compound-stub Photogr ...
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Chromogenic
In chemistry, the term chromogen refers to a colourless (or faintly coloured) chemical compound that can be converted by chemical reaction into a compound which can be described as "coloured". There is no universally agreed definition of the term. Various dictionaries give the following definitions: * A substance capable of conversion into a pigment or dye. * Any substance that can become a pigment or coloring matter, a substance in organic fluids that forms colored compounds when oxidized, or a compound, not itself a dye, that can become a dye. * Any substance, itself without color, giving origin to a coloring matter. In biochemistry the term has a rather different meaning. The following are found in various dictionaries. * A precursor of a biochemical pigment * A pigment-producing microorganism * Any of certain bacteria that produce a pigment * A strongly pigmented or pigment-generating organelle, organ, or microorganism. Applications in chemistry *In chromogenic photography, f ...
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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 company that started as a manufacturer of photographic films, which it still produces, include: document solutions, medical imaging and diagnostics equipment, cosmetics, pharmaceutical drugs, regenerative medicine, stem cells, biologics manufacturing, magnetic tape data storage, optical films for flat-panel displays, optical devices, photocopiers and printers, digital cameras, color films, color paper, photofinishing and graphic arts equipment and materials. Fujifilm is part of the Sumitomo Mitsui Financial Group financial conglomerate (''keiretsu''). History 20th century Fuji Photo Film Co., Ltd. was established in 1934 as a subsidiary of Daicel with the aim of producing photographic films. Over the following 10 years, the comp ...
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Agfa-Gevaert
Agfa-Gevaert N.V. (Agfa) is a Belgian-German multinational corporation that develops, manufactures, and distributes analogue and digital imaging products, software, and systems. It has three divisions: * Agfa Graphics, which offers integrated prepress and industrial inkjet systems to the printing and graphics industries. * Agfa HealthCare, which supplies hospitals and other care organisations with imaging products and systems, and information systems. * Agfa Specialty Products, which supplies products to various industrial markets. It is part of the Agfa Materials organization. In addition to the Agfa Specialty Products activities, Agfa Materials supplies film and related products to Agfa Graphics and Agfa HealthCare. Agfa film and film cameras were once prominent consumer products. However, in 2004, the consumer imaging division was sold to a company founded via management buyout. AgfaPhoto GmbH, as the new company was called, filed for bankruptcy after just one year,
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Gloss (optics)
Gloss is an optical property which indicates how well a surface reflects light in a specular (mirror-like) direction. It is one of the important parameters that are used to describe the visual appearance of an object. The factors that affect gloss are the refractive index of the material, the angle of incident light and the surface topography. Apparent gloss depends on the amount of ''specular'' reflection – light reflected from the surface in an equal amount and the symmetrical angle to the one of incoming light – in comparison with ''diffuse'' reflection – the amount of light scattered into other directions. Theory When light illuminates an object, it interacts with it in a number of ways: * Absorbed within it (largely responsible for colour) * Transmitted through it (dependent on the surface transparency and opacity) * Scattered from or within it (diffuse reflection, haze and transmission) * Specularly reflected from it (gloss) Variations in surface texture directly ...
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Photographic Developer
In the processing of photographic films, plates or papers, the photographic developer (or just developer) is one or more chemicals that convert the latent image to a visible image. Developing agents achieve this conversion by reducing the silver halides, which are pale-colored, into silver metal, which is black (when a fine particle).Karlheinz Keller et al. ''Photography'' in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2005, Wiley-VCH, Weinheim. The conversion occurs within the gelatine matrix. The special feature of photography is that the developer acts more quickly on those particles of silver halides that have been exposed to light. Paper left in developer will eventually reduce all the silver halides and turn black. Generally, the longer a developer is allowed to work, the darker the image. Chemical composition of developers The developer typically consists of a mixture of chemical compounds prepared as an aqueous solution. For black-and-white photography, three ...
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Darkroom
A darkroom is used to process photographic film, to make prints and to carry out other associated tasks. It is a room that can be made completely dark to allow the processing of the light-sensitive photographic materials, including film and photographic paper. Various equipment is used in the darkroom, including an enlarger, baths containing chemicals, and running water. Darkrooms have been used since the inception of photography in the early 19th century. Darkrooms have many various manifestations, from the elaborate space used by Ansel Adams to a retooled ambulance wagon used by Timothy H. O'Sullivan. From the initial development of the film to the creation of prints, the darkroom process allows complete control over the medium. Due to the popularity of color photography and complexity of processing color film (''see C-41 process'') and printing color photographs and also to the rise, first of instant photography technology and later digital photography, darkrooms are dec ...
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Chromogenic Print
A chromogenic print, also known as a C-print or C-type print, a silver halide print, or a dye coupler print, is a photographic print made from a color negative, transparency or digital image, and developed using a chromogenic process. They are composed of three layers of gelatin, each containing an emulsion of silver halide, which is used as a light-sensitive material, and a different dye coupler of subtractive color which together, when developed, form a full-color image. History Developing color by using oxidized developers was first suggested by German chemist Benno Homolka who, in 1907, successfully developed insoluble indigo-blue and red dyes on a latent image by oxidizing indoxyl and thio-indoxyl respectively. He additionally noted these developers could create beautiful photographic effects. The potential of oxidized developers in a color photographic process however, was first realized by another German chemist, Rudolf Fischer, who, in 1912, filed a patent describing ...
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