Foundations of Digital Image

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10. Display Types

CRT Screen

A cathode ray tube (CRT) is a vacuum tube containing an electron gun (a source of electrons or electron emitter) and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam(s) onto the fluorescent screen to create images.

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Nam Jun Paik video sculpture, CRT screen and the magnet, 1965

Flat Screen Types 

LCD Screen

A liquid crystal display (LCD) does not illuminate, requiring a separate light source. They are used in a wide range of applications including computer monitors, televisions, instrument panels, aircraft cockpit displays, and signage. They are common in consumer devices such as video players, gaming devices, clocks, watches, calculators, and telephones, etc.

LED Screen

Screens for TV and computer displays can be made thinner using light-emitting diodes (LEDs) for backlighting.

Plasma Screen

Plasma phosphors that create images on the screen light up themselves and don’t require backlighting.

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Jon Kessler, Installation view, “the Web” Swiss Institute, 2013

The Web offers both an accessible and impermeable user experience, the title referencing a closed-circuit network accessed by viewers. Upon entering the exhibition, visitors are invited to download an iPhone app that feeds their images in real time onto surrounding monitors. Simultaneously pictured and reframed in Kessler’s sculpture Infinite Regress, spectators render themselves as nodes within a feedback network, the space a physical support for their virtual daydreams. Kessler’s creation broadcasts collected data, targeting viewers with images of themselves, their experience, and ultimately enticing input and generating output.

Projection technologies

CRT projectors use cathode ray tubes. This typically involves a blue, a green, and a red tube. This is the oldest system still in regular use, but falling out of favor largely because of the bulky cabinet. However, it does provide the largest screen size for a given cost. This also covers three tube home models, which, while bulky, can be moved (but then usually require complex picture adjustments to get the three images to line up correctly).

LCD projectors use LCD light gates. This is the simplest system, making it one of the most common and affordable options for home theaters and business use. Its most common problem is a visible “screen door” or pixelation effect, although recent advances have reduced the severity of this effect.

DLP projectors use Texas Instruments’ DLP technology. This uses one, two, or three microfabricated light valves called digital micromirror devices (DMDs). The single- and double-DMD versions use rotating color wheels in time with the mirror refreshes to modulate color. The most common problem with the single- or double-DMD varieties is a visible rainbow, which some people perceive when moving their eyes. More recent projectors with higher speed (2x or 4x) and optimized color wheels have lessened this effect. Systems with triple-DMDs never have this problem, as they display each primary color simultaneously.

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LCoS projector using Liquid crystal on silicon.

lcos-projector

LED projectors use one of the above mentioned technologies for image creation, with a difference that they use an array of Light Emitting Diodes as the light source, negating the need for lamp replacement.

led-diagram

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Untitled, 2013

51″ x 34″
digital inkjet print

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Not yet titled, 2014

60″ x 40″
digital inkjet print

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Surface Projection #7, 2013

34″ x 51″
digital inkjet print

Projection Mapping - Box Box by Bot & Dolly | Behind the Scenes

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augmented sculpture series, Pablo Valbuena, 2007

augmented sculpture series

Plasma screen:

Hito Steyerl, Strike, 2010

http://www.youtube.com/watch?v=WpGobhaYT8Y

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