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Aspect Ratio Definition
This is an attribute of image projection that gives a description of the width of an image and its proportional relationship its height.
A Little More on What is Aspect Ratio
The Aspect ratio is a description of the rectangle on the TV screen which limits the image information in the recording, projection or playback. The width divided by the height of the rectangle is the aspect ratio, and so the proportion of the rectangle describes the image section as in geometry.
The aspect ratio of super 8 and average 16 is 4:3 and sometimes 1.33:1. In some cases, though rare, filmmakers shoot in the 4:3 ratio. The film ‘Mommy’ was shot over long distances in a quadratic aspect ratio. A full image area uses a 1.33:1 ratio.
In television screens for a long time, an aspect ratio of 1.375:1 was used. It was called the Academy Standard. This was because the early television sets were based on the cinema standard which at the time was 1.375:1. This was back in the 1940s and 1950s. However, since the introduction of high-definition televisions nowadays, there is a need for other aspect ratios which are close to the cinema standard of 1.77:1.
Now in the cinema, there is a widescreen format of 1.66:1. However, the desire to produce wide images has made the aspect ratio standard to be 1.85:1 since most movies come in this ratio. This is very different from the image area which usually has a 35mm film image and therefore uses less of the height.
In this kind of situation, for it to rotate in 1.85:1, there must be a corresponding image used in the camera, and this cuts off upper and lower parts of the film. Another way of accomplishing this is by drawing the image section in 1.85:1 in a viewfinder. Despite all this, much film material is still wasted.
In the past, there was an effort to change the 35mm standard by moving only three instead of four perforations of footage at each image using a technique called Techniscope. This was aimed at saving lots of raw films. However, the last attempt in this technique was called 3perf, and it did not yield expected results.
Widescreen methods like the Cinemascope widen the picture again to reach a ratio of 2.35:1. This format consequently produces black bars on the screen. The widescreen televisions solve this problem by using a correspondingly widened format like in HDTV. Therefore, only cinemascope movies produce black bars on the screen. This format was introduced to offer better visual attractions than the competition which was television back in the 1950s.
Film or video cameras have a single-lens reflex finder which can be used to realize different image formats. There are matt screens on which nearly all the essential aspect ratios are drawn simultaneously. To work with such a screen, one needs to get used to it and also concentrate more on the image. Because of this, many camera operators prefer to use their screen on the viewfinder for every aspect ratio used.
Combined focusing screens were mostly used in the 1990s when TV broadcasters propagated thinking which was used with the following name ‘Shoot and Protect.’ This meant that people were to make simultaneously, the image design for two formats.
The first was the design for the typical TV sets at that time which was 4:3 and that for future repeats of the same movie in 16:9 which was HDTV. Nobody, however, was able to explain how it should work to achieve an optimal image design for both image formats.
References for Aspect Ratio
Academic Research for Aspect Ratio
- Hot embossing as a method for the fabrication of polymer high aspect ratio structures, Becker, H., & Heim, U. (2000). Sensors and Actuators A: Physical, 83(1-3), 130-135. This paper presents the technology of hot embossing as a flexible and low-cost method of microfabrication for polymer microstructures, and which replicates a micromachined embossing master to generate microstructures on a polymer substrate.
- High-aspect-ratio, ultra thick, negative-tone near-UV photoresist and its applications for MEMS, Lorenz, H., Despont, M., Fahrni, N., Brugger, J., Vettiger, P., & Renaud, P. (1998). Sensors and Actuators A: Physical, 64(LMIS4-ARTICLE-1998-001), 33-39. This paper presents the detailed investigations on the limits of a new negative-tone near-UV resist IBM SU-8 which is an epoxy-based resist designed for ultra-thick, high aspect ratio MEMS-type applications.
- Advanced etching of silicon based on deep reactive ion etching for silicon high aspect ratio microstructures and three-dimensional micro-and nanostructures, Marty, F., Rousseau, L., Saadany, B., Mercier, B., Français, O., Mita, Y., & Bourouina, T. (2005). Microelectronics Journal, 36(7), 673-677. This study presents the various processes that involve an inductively coupled plasma reactor for either deep reactive ion etching or isotopic etching of silicon.
- SU-8: a photoresist for high-aspect-ratio and 3D submicron lithography, Del Campo, A., & Greiner, C. (2007). Journal of Micromechanics and Microengineering, 17(6), R81. This article details how SU-8 has become the preferred photoresist for high-aspect-ratio (HAR) and three-dimensional lithographic patterning due to its excellent properties and mechanical and chemical stability.
- Rapid synthesis of high aspect ratio copper nanowires for high-performance transparent conducting films, Ye, S., Rathmell, A. R., Stewart, I. E., Ha, Y. C., Wilson, A. R., Chen, Z., & Wiley, B. J. (2014). Chemical Communications, 50(20), 2562-2564. This is a presentation of a method of producing copper nanowires with aspect ratios of up to 5700 in just thirty minutes and also describes the growth processes which are responsible for their formation.
- A study on the machining of high-aspect-ratio micro-structures using micro-EDM, Lim, H. S., Wong, Y. S., Rahman, M., & Lee, M. E. (2003). Journal of Materials Processing Technology, 140(1-3), 318-325. This paper separates the machining of microstructures into two basic processes which are the on-machine fabrication of micro-electrodes with high-aspect ratio and the EDM of the work piece in the micrometer range.
- Seam carving for content-aware image resizing, Avidan, S., & Shamir, A. (2007, August). (Vol. 26, No. 3, p. 10). ACM. This article presents an image operator called seam carving that is simple and supports content-aware image resizing for reduction and expansion.
- Novel high aspect ratio aluminum plug for logic/DRAM LSIs using polysilicon-aluminum substitute (PAS), Horie, H., Imai, M., Itoh, A., & Arimoto, Y. (1996, December). In Electron Devices Meeting, 1996. IEDM’96, International (pp. 946-948). IEEE. This paper describes a polysilicon-aluminum substitute (PAS) technique for single-crystalline aluminum plugs which possess aspect ratios of over seven and used for sub-quarter micron logic/DRAM LSIs.