Misplaced Pages

#627372

27-404: The Technirama process used a film frame area twice as large as CinemaScope. This gave the former a sharper image with less photographic grain . Cameras used 35mm film running horizontally with an 8-perforation frame, double the normal size, exactly the same as VistaVision . VistaVision cameras were sometimes adapted for Technirama. Technirama used 1.5:1 anamorphic curved mirror optics in front of

54-440: A bit less than those processes, because the negative was not quite as large and needed to be printed optically. Technicolor had roughly 12 of its three-strip Technicolor cameras converted into VistaVision cameras, using camera movements supplied by Mitchell Camera Corporation , the 1932 supplier of the original three-strip camera movements. After the 1956 delivery to Paramount Pictures Corporation by Mitchell Camera Corporation of

81-463: A digital camera operating in low light conditions does result in a noisy image, but the visual appearance is somewhat different from traditional photographic film. The visual and artistic effect of film grain can be simulated in some digital photo manipulation programs by adding grain to a digital image after it is taken. Various raw image processing software packages (such as RawTherapee and DxO PhotoLab ) feature "film simulation" effects that apply

108-436: A digital file. This process adds film grain characteristics, and in instances with moving images, subtle flicker to the more sterile looking digital medium. As opposed to computer plug-ins, FGO is typically derived from actual film grain samples taken from film, shot against a gray card. Because film grain is difficult to encode because of its random nature, some video codecs, notably AV1 , include film grain synthesis, where

135-426: A film with granularity 10 means an rms density fluctuation of 0.010 in the standard aperture area. When the particles of silver are small, the standard aperture area measures an average of many particles, so the granularity is small. When the particles are large, fewer are averaged in the standard area, so there is a larger random fluctuation, and a higher granularity number. Film grain is also sometimes quantified in

162-430: A more light-sensitive center is surrounded by more developer-sensitive shell. This gives finer grain for the same film speed. One of possibilities is a iodide-rich core and iodide-poor shell, giving high sensitivity to light inside and high sensitivity to developer outside. Both morphologies can also come in different distribution of sizes; "monosize", with narrow distribution of crystal dimensions, gives better control of

189-463: A way that is relative independent of size of the aperture through which the microdensitometer measures it, using R. Selwyn's observation (known as Selwyn's law) that, for a not too small aperture, the product of RMS granularity and the square root of aperture area tends to be independent of the aperture size. The Selwyn granularity is defined as: G = σ 2 a {\displaystyle G=\sigma {\sqrt {2a}}} where σ

216-664: Is a bit of evidence that horizontal prints were envisioned for Technirama as well (probably with 4-track magnetic sound as in CinemaScope ), but to what extent this was ever done commercially, if at all, remains unclear. The name Super Technirama 70 was used on films where the shooting was done in Technirama and at least some prints were made on 70mm stock by unsqueezing the image. Such prints would be compatible with those made by such 65mm negative processes as Todd-AO and Super Panavision . The quality would have been very good but perhaps

243-454: Is a numerical quantification of density non-uniformity, equal to the root-mean-square (rms) fluctuations in optical density, measured with a microdensitometer with a 0.048 mm (48-micrometre) diameter circular aperture, on a film area that has been exposed and normally developed to a mean density of 1.0 D (that is, it transmits 10% of light incident on it). Granularity is sometimes quoted as "diffuse RMS granularity times 1000", so that

270-429: Is not an inherent property of tabular crystals but rather the result of other techniques introduced at about the same time. 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

297-668: Is the RMS granularity and a is the aperture area. The images below show an example of extreme film grain: Digital photography does not exhibit film grain, since there is no film for any grain to exist within. In digital cameras, the closest physical equivalents of film grains are the individual elements of the image sensor (e.g. CCD cell ), the pixels; just as small-grain film has better resolution but less sensitivity than large-grain film, so will an image sensor with more elements result in an image with better resolution but less light per pixel. Thus, like film grain, physical pixel size represents

SECTION 10

#1732844306628

324-461: The Fujifilm Neopan films. The silver halide crystals in the film emulsion are flatter and more tabular (hence T-Grain). 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

351-448: The Ag 4 clusters that start the autocatalytic process of development. Large crystals will therefore give more sensitive film, for the price of being visibly grainier. Fine grain better preserves details but requires more light. Tabular-grain film uses crystals of flat morphology, with width-to-thickness ratios of at least two, often much more. The flat morphology allows better overlapping of

378-482: The camera lens (unlike CinemaScope's cylindrical lenses which squeezed the image in a 2:1 ratio). In the laboratory, the 8-perforation horizontal negative would be reduced optically, incorporating a 1.33:1 horizontal squeeze to create normal 4-perforation (vertically running) prints with images having an anamorphic squeeze ratio of 2:1. Just as VistaVision had a few flagship engagements using 8-perf horizontal contact prints and special horizontal-running projectors, there

405-511: The characteristics of various film brands, including the graininess. Plugins for the same purpose also exist for various image editors such as Photoshop (e.g. in Nik Collection 's Analog Efex and Silver Efex). In digital photography, image noise sometimes appears as a "grain-like" effect. Film grain overlay, sometimes referred to as "FGO", is a process in which film emulsion characteristics are overlaid using different levels of opacity onto

432-476: The compromise between resolution and sensitivity. However, while film grains are randomly distributed and have size variation, image sensor cells are of same size and are arranged in a grid, so direct comparison of film and digital resolutions is not straightforward. Instead, the ISO setting on a digital camera controls the gain of the electronic amplifier on the readout circuitry of the chip. Ultimately, high ISO settings on

459-441: 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

486-572: The crystals, reducing intergranular space and giving more black for the same amount of silver. The more compact structure allows for thinner emulsion layers. It is also more difficult to wash during the fixing stage. Tabular crystals also better absorb sensitizing dyes. They also scatter the light less, giving sharper image but less gradation. Tabular crystals also have less chance of absorbing high energy photons from ambient and cosmic radiation, giving longer shelf life without fogging. The tabular crystals can be favored during synthesis by an extra step, where

513-474: 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

540-466: The film grain is removed during encoding and replaced with parameters that describe the shape and density of the particles, and during playback the decoder uses these parameters to resynthesize the film grain. Tabular-grain film 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

567-452: The film speed and less visible grain (due to absence of larger crystals). Wider, more random size variation gives more tolerance to exposure (for too little light there are some big crystals, for too much light there are some little grains), and more tolerance to development process. Rod-shaped grains, the opposite to tabular grains, can undergo self-development even in absence of light, resulting in fogging. Granularity, or RMS granularity,

SECTION 20

#1732844306628

594-464: The formed crystal seeds of undesired morphology are dissolved and the remaining ones grow by controlled Ostwald ripening . "Classical", cubic-grain emulsion provides more random distribution of the crystal shapes and sizes, resulting in more "forgiving" film tolerant to wider range of exposures. Both morphologies can also be modified for a core-shell structure, with a small silver halide grain being surrounded by one or more light-capturing layers, or

621-444: 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

648-629: The newly designed and constructed Mitchell VistaVision cameras, the converted Technicolor three-strip cameras immediately became obsolete, and were surplus to Technicolor's operations. These converted three-strip VistaVision cameras thereafter became the standard Technirama cameras, which were subsequently supplemented by a few Paramount hand-held VistaVision cameras fitted with anamorphic optics. The logistical advantage of using 35mm film, end-to-end, should not be underestimated. A few 8-perf titles have been preserved on 65mm film, but most have been preserved on 35mm film or are considered unprintable. The color

675-620: The same thing as such. It is an optical effect, the magnitude of which (amount of grain) depends on both the film stock and the definition at which it is observed. It can be objectionably noticeable in an over-enlarged film photograph. The size and morphology of the silver halide grains play crucial role in the image characteristics and exposure behavior. There is a tradeoff between the crystal size and light sensitivity ( film speed ); larger crystals have better chance to receive enough energy to flip them into developable state, as they have higher probability of receiving several photons needed for forming

702-605: Was enhanced through the use of a special development process that was used to good effect in films such as The Vikings (1958) and The Music Man (1962). However, fewer than 40 films were produced using this process in the United States . It was more popular and longer-lasting in Europe. Walt Disney Productions used the process twice for full-length animated features: Sleeping Beauty (1959), and The Black Cauldron (1985). The 2008 DVD and Blu-ray Disc release of Sleeping Beauty

729-440: Was shown at an aspect-ratio of 2.55:1 for the first time. Film grain Film grain or film granularity is the random optical texture of processed photographic film due to the presence of small particles of a metallic silver, or dye clouds, developed from silver halide that have received enough photons. While film grain is a function of such particles (or dye clouds) it is not

#627372