Tipos de liderazgo educativo

Within the fixed and clearly defined space of the TV screen, there operate specific field forces that are quite different from those of an undefined space, such as our actual three-dimensional environment or location space. Some of these characteristics are:

 Display size- Sometimes called viewable image size or VIS, display size is the physical size of the area where pictures and videos are shown. The diagonal

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length of the screen usually describes it. This size is limited and specific to a given television screen. A television display screen shows television images in three planes i.e. vertical, horizontal and diagonal planes. Although a film or television image cannot be categorized as oversized or undersized, it is true however that the sheer size of a television image has some aesthetic consequences. A large film image feels more overpowering than a small image of the same event. The larger image will definitely carry more aesthetic energy.

But a large image must be shown on a large screen! Also, there are more details to an event if close up shots are used. This helps the viewer to look into the event through a series of details in the pictures.

 Display resolution- Display resolution refers to the number of pixels in each dimension on a display. All television sets have resolutions. When we talk about picture resolution, we are talking about the resolution of the television screen as well as the resolution of the source video like cameras, DVDs, cables etc. Both the source video resolution and the television screen resolution are important, and each can affect the other in defining the quality of the picture we see. A television screen resolution is defined by, the materials used in making the screen as well as those used in producing the pictures. If material resolution is too low, pixilation will occur on our display screen. If material resolution is too high, there will be motion sickness or artifacts. The two must be a commeasure.

 Aspect Ratio-This is the ratio of display width to display height. Television screens come in different ratios; 4:3, 16:9 etc. The former is no longer popular as television screens now use the 16:9 ratio found on High Definition Television sets. There are two types of aspect ratios: Original aspect ratio which is the dimension in which the film is originally produced and modified aspect ratio which is the dimensions in which the original film is altered to fit a particular screen. The wide screen ratio is popular amongst movie studios which scramble to make films on large screens that will do away with the dominance of television and introduce to movie goers a feeling that makes them part of an on- screen action.

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 Frame Rate- All television screens have frame rates. Frame rates vary between Countries. This is because frame rate is tied to a Country's public power supply system. It is calculated by halving the frequency of a Country's power supply. Countries like Nigeria and other British Colonies whose power supply frequency is 50Hz (cps), we use television sets with 25 fps, while American countries use that with 30 fps because the frequency of their supply is 60Hz (cps). Sadly, the decisions on which aspect ratio or frame rate to use are not creative but based on the final distribution of the production or the technical limitations of the equipment being used.

 Viewing angle-When you are alone watching a television screen, there is perhaps a tendency for you to sit centrally facing the screen and so have no challenges to viewing angle. If a group of persons sit to watch the same screen, challenges exist because the quality of the television signal is affected by what angle of the television screen one sits to watch. All television sets have specification for viewing angles. Viewing angles are measured horizontally and vertically and indicate over what range, images on the screen are fully visible without the screen displaying a negative image. With less viewing angle, picture quality is lost. A viewing angle can be improved by adjusting wall mounts of a screen to make them tilt to a direction that offers better viewing experience.

 Viewing distance - This is the distance between the viewer and the television screen. Viewing distance is related to display size. Changing viewing distance is similar to changing television size. There are a number of factors that can affect the calculation and selection of a particular viewing distance. These are;

human physiological considerations, technological limitations of television sets and the contents to be viewed. Technical limitations of television sets include the maximum detail perception of a television set and the high definition resolution materials on television sets. Maximum detail perception of a television set is mostly noticed on HD flat panel televisions sets. On these sets, the image is formed on a grid of tightly packed pixels. If this image is watched from a small distance, pixel lines or pixilation will appear on the screen.

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