Ilfochrome

Last updated

Ilfochrome (also commonly known as Cibachrome) is a dye destruction positive-to-positive photographic process used for the reproduction of film transparencies on photographic paper. The prints are made on a dimensionally stable polyester base as opposed to traditional paper base. Since it uses 13 layers of azo dyes sealed in a polyester base, the print will not fade, discolour, or deteriorate for an extended time. Accelerated aging tests conducted by Henry Wilhelm rated the process as producing prints which, framed under glass, would last for 29 years before color shifts could be detected. [1] Characteristics of Ilfochrome prints are image clarity, color purity, and being an archival process able to produce critical accuracy to the original transparency.

Contents

History

Dr. Bela Gaspar created Gasparcolor, the dye bleach process upon which the Cibachrome process was originally based. It was considered vital to the war effort in the 1940s. Gaspar turned down many offers to sell the rights to his process and after he died, Paul Dreyfus, who was the chemist and technician for Gaspar, went to work for CIBA AG. When the patents ran out, he developed the process for Cibachrome. (Frozen Moments - Richard C. Miller) In the 1960s, the Cibachrome process was originally engineered by the Ciba Geigy Corporation of Switzerland. Ciba acquired Ilford in 1969, [2] and sold it to International Paper in 1989; [3] in 1992 [4] the product was renamed to "Ilfochrome". Colloquially, however the process is still referred to as "Cibachrome".

Before 2004 Ilford Ltd had two main manufacturing sites: Mobberley in the UK, where most traditional products were made, and Fribourg (Freiburg) in Switzerland, where Ilfochrome and Ilfocolor papers were made, as well as the inkjet papers. The UK side was subject to a management buyout, and the Swiss operation (Ilford Imaging Switzerland GmbH) was sold to the Japanese Oji paper group in 2005 and to Paradigm Global Partners LLP in 2010. The Swiss plant retained the Ilford name, while the UK operation was inaugurated under the name HARMAN, taken from the name of the founder of the original Britannia Works. Ilford Photo HARMAN Technology Ltd can still use the Ilford brandname and logo under license on previously existing products, while new products will carry the Harman name.

In 2012, Ilford announced its final production run of Ilfochrome Classic in response to declining market demand attributed to the expanding popularity of digital image making.

Advantages

The composition of the emulsion used in Ilfochrome prints is responsible for color purity, image clarity, and archival permanence. Azo dyes, which provide stable vivid colors, are embedded in the Ilfochrome emulsion and bleached out in processing. Since the dyes are in the emulsion rather than in the chemistry[ clarification needed ], the image is also much sharper and clearer because the dyes create an anti-light-scattering layer which keeps the image from being diffused when viewed. As the azo dyes are far more stable than chromogenic dyes, prints made by this process are of archival quality and galleries and art collectors report they do not fade in normal light.

Use directly in camera

An alternative use of Ilfochrome was for image capture directly inside a large format or ultra large format camera. This created a unique original positive photograph, in which the subject is reversed left-right unless a mirror or prism was used in front of the camera lens. A much longer exposure was required than with sheet films or plates designed for use in a camera. The procedure thus resembled the slow daguerreotype and ambrotype direct positive black-and-white processes used in the 1850s. [5] [6]

Sources

Related Research Articles

Film stock Medium used for recording motion pictures

Film stock is an analog medium that is used for recording motion pictures or animation. It is recorded on by a movie camera, developed, edited, and projected onto a screen using a movie projector. It is a strip or sheet of transparent plastic 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 the sensitivity, contrast and resolution of the film. The emulsion will gradually darken if left exposed to light, but the process is too slow and incomplete to be of any practical use. Instead, a very short exposure to the image formed by a camera lens is used to produce only a very slight chemical change, proportional to the amount of light absorbed by each crystal. This creates an invisible latent image in the emulsion, which can be chemically developed into a visible photograph. In addition to visible light, all films are sensitive to X-rays and high-energy particles. Most are at least slightly sensitive to invisible ultraviolet (UV) light. Some special-purpose films are sensitive into the infrared (IR) region of the spectrum.

Photographic processing or photographic development is the chemical means by which photographic film or paper is treated after photographic exposure to produce a negative or positive image. Photographic processing transforms the latent image into a visible image, makes this permanent and renders it insensitive to light.

Photographic paper Light-sensitive paper used to make photographic prints

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 but other alternatives have also been used.

Reversal film

In photography, reversal film or slide film is a type of photographic film that produces a positive image on a transparent base. Instead of negatives and prints, reversal film is processed to produce transparencies or diapositives. Reversal film is produced in various sizes, from 35 mm to roll film to 8×10 inch sheet film.

Photographic developer

In the processing of photographic films, plates or papers, the photographic 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. 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.

Photographic printing is the process of producing a final image on paper for viewing, using chemically sensitized paper. The paper is exposed to a photographic negative, a positive transparency , or a digital image file projected using an enlarger or digital exposure unit such as a LightJet printer. Alternatively, the negative or transparency may be placed atop the paper and directly exposed, creating a contact print. Digital photographs are commonly printed on plain paper, for example by a color printer, but this is not considered "photographic printing".

C-41 is a chromogenic color print film developing process introduced by Kodak in 1972, superseding the C-22 process. C-41, also known as CN-16 by Fuji, CNK-4 by Konica, and AP-70 by AGFA, is the most popular film process in use, with most photofinishing labs devoting at least one machine to this development process.

Photographic print toning

In photography, toning is a method of changing the color of black-and-white photographs. In analog photography, it is a chemical process carried out on metal salt based prints such as Silver Prints, Iron Based Prints, Platinum or Palladium Prints photographic prints. This darkroom process cannot be performed with a color photograph. The effects of this process can be emulated with software in digital photography. Sepia is considered a form of Black and White or Monochromatic Photography.

ADOX

The ADOX brand for photographic purposes has been used by three different companies since its original conception over one hundred fifty years ago. ADOX was originally a brand name used by the German company, Fotowerke Dr. C. Schleussner GmbH of Frankfurt am Main, the world's first photographic materials manufacturer. In 1962 the Schleussner family sold its photographic holdings to DuPont, an American company. DuPont used the brand for its subsidiary, Sterling Diagnostic Imaging for X-ray films. In 1999, Sterling was bought by the German company Agfa. Agfa did not use the brand and allowed its registration to lapse in 2003. Fotoimpex of Berlin, Germany, a company founded in 1992 to import photographic films and papers from former eastern Europe immediately registered the brand and today ADOX is a brand of black and white films, photographic papers and photochemistry produced by ADOX Fotowerke GmbH based in Bad Sarrow near Berlin.

Ilford Photo British photographic materials company

Ilford Photo is a UK manufacturer of photographic materials known worldwide for its black-and-white film and papers and chemicals, and its range of Ilfochrome and Ilfocolor colour printing materials, before these were discontinued. Ilfochrome was formerly called Cibachrome, developed in partnership with the Swiss company CIBA-Geigy. Formerly, it published the Ilford Manual of Photography, a comprehensive manual of everything photographic, including the optics, physics and chemistry of photography, along with recipes for many developers.

Chromogenic photography is photography that works by a chromogen forming a conventional silver image and then replacing it with a dye image. Most films and papers used for color photography today are chromogenic, using three layers, each providing their own subtractive color. Some chromogenic films provide black-and-white negatives, and are processed in standard color developers. In this case, the dyes are a neutral color.

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.

Color motion picture film

Color motion picture film refers both to unexposed color photographic film in a format suitable for use in a motion picture camera, and to finished motion picture film, ready for use in a projector, which bears images in color.

Dye destruction or dye bleach is a photographic printing process, in which dyes embedded in the paper are bleached (destroyed) in processing. Because the dyes are fully formed in the paper prior to processing, they may be formulated with few constraints, compared to the complex dye couplers that must react in chromogenic processing. This method has allowed the use of richly colored, highly stable dyes. It is a reversal process, meaning that it is used in printing transparencies (diapositives).

The following outline is provided as an overview of and topical guide to photography:

Photographic film Film used by film (analog) cameras

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 the sensitivity, contrast, and resolution of the film.

Mordançage

Mordançage is an alternative photographic process that alters silver gelatin prints to give them a degraded effect. The mordançage solution works in two ways: it chemically bleaches the print so that it can be redeveloped, and it lifts the black areas of the emulsion away from the paper giving the appearance of veils. Once the emulsion is lifted, it can then be removed or manipulated depending on the desired outcome. Areas where the emulsion was removed appear to be in relief. These prints can become oxidized during their creation, further altering the tonality of the image.

The conservation and restoration of film is the physical care and treatment of film-based materials. These include photographic film and motion picture film stock.

References

  1. ↑ Wilhelm, Henry (2006). "A 15-Year History of Digital Printing Technology and Print Permanence in the Evolution of Digital Fine Art Photography - From 1991 to 2006" (PDF). Society for Imaging Science and Technology. Retrieved 17 April 2018.
  2. ↑ Araujo, Anderson. "Ilford chronology". Ciba 1963. Retrieved 2011-11-13.
  3. ↑ Araujo, Anderson. "Ilford chronology". Ciba 1989. Retrieved 2011-11-13.
  4. ↑ Araujo, Anderson. "Ilford chronology". Ciba 1992. Retrieved 2011-11-13.
  5. ↑ Annaratone, Marco. "Going Ultra: Ultra Large Format and In-Camera Ilfochrome" (PDF). Going Ultra. Archived from the original (PDF) on 2016-03-03. Retrieved 2008-02-25.
  6. ↑ Evans, Glenn. "Shooting Cibachrome in-camera". Glennview. Retrieved 2008-02-25.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.