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A comparison between electronic and film-based cinema systems and perspectives of their developmentV.G. Komar (Leading Researcher, NIKFI - Cine&Photo Research Institute)
A comparison between the image qualities ensured by various developed and used electronic and film-based cinema systems reveals that HDTV-based cinema systems on some parameters surpass and on other parameters concede to cinema systems using the 35mm film. On the whole, in terms of the image quality these two systems are close to each other and practically equivalent. Thus, some directors, experts and viewers prefer electronic cinema using a HDTV standard but some prefer 35mm-film cinema. Best mixed (intermediate) cinema systems containing a cascade of both electronic and film-based links, in terms of the image quality, are practically equivalent with the above-mentioned digital HDTV standards and 35mm film systems. Resolution of best negative films of 35mm format, expressed in pixels based on the image sharpness, is slightly less than that of CCD sensors used in TV cameras (1920x1080 pixels). Resolution of best positive films of 35mm format, expressed in pixels based on the image sharpness, is higher than that of light modulators used in video projectors. However, on the whole (from shooting to projection), these and best mixed systems have close values of resolution defined in terms of image sharpness. It is important to note that cinema systems using 35mm films essentially surpass HDTV electronic and mixed systems in resolution, expressed in pixels based on small detail rendition. Because of that, many directors, experts and viewers note better reproduction of fine structures of many real-world objects. Colour gamut of best digital cinema systems surpasses that of film-based scope cinema systems. However, this superiority is of no vital importance in practice, since colour gamut of films enables to reproduce well colour of subjects, characteristic for a cinema. Count of reproduced halftones and colour shades of the image ensured by film-based systems is well over that of digital systems. However, when using the12-bit quantization for three primary colours (red, green and blue) used in best digital systems, this superiority is of no vital importance in practice because of limitations of the human vision system. Simpler and faster colour correction characteristic for digital systems, is a major advantage of such systems, especially in the process of exploitation. The image contrast and latitude of exposure are practically identical in compared systems. The image artefacts such as graininess, scratches and spots are disadvantages of film-based systems, especially in long-term exploitation. The possibility of unlimited, eternal storage of films in a digital form by successive re-recording of film copies is a major advantage of digital processes. Stability of the image on the screen in modern electronic systems is much better than that in existing 35mm-film cinema systems. Sound quality in electronic systems can be as high as in film-based systems. A comparison between economic characteristics ensured by electronic and film-based cinema systems reveals that HDTV-based cinema systems on some economic characteristics surpass and on other characteristics concede to cinema systems using the 35mm film. Current financial expenses in making digital films both for theatrical and television presentations are appreciably less than that in making celluloid films. However, electronic film production needs essential expenses to purchase or rent the required equipment. Production and delivery to movie theatres of electronic film copies as videocassettes or videodiscs is much cheaper than that of celluloid film copies. Providing movie theatres with the up-to-day digital equipment and servicing it with the help of more qualified staff, is more expensive than that in case of film-based equipment, this fact being is a serious reason of sufficiently slow transition from film-based systems to electronic systems. Because of that, it is possible to expect a practical usage of the mixed cinema systems in rather great volumes. Satellite transmissions of electronic film signals may be economically feasible on a relatively scale. On the basis of the stated above, one should believe that within the current decade an HDTV-based electronic cinema is to receive very wide applications not only in television but also in movie theaters. Along with it, film-based cinema will continue to be used on an enormous scale. By the end of this decade, it is possible to expect the establishment of an electronic cinema system using CCD sensors and light modulators of higher horizontal resolution, e.g. the 4К resolution. In many countries, the research work is going on with the aim of developing electronic cinema systems with the three-dimensional image. In co-operation with the Moscow State University and several Russian companies, and also with the Korean Institute of a Science and Technology and the Hannam University (South Korea), the Cine&Photo Research Institute conducts research works in this field. |
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