You are here


Presentation Factors

Consider these technical factors related to picture presentation on display panels: contrast ratio, black level performance, colour accuracy, viewing angle, supported picture detail. These factors too need to be kept in mind before one makes the final choice.

Black level performance: The picture quality depends on not only what is inside but also the exteriors, that is, the lighting. Under controlled lighting in the surroundings, Plasma provides better picture quality. As explained in the working principle of Plasma TVs, there is nil leakage of light between the adjacent gas cells. This property enables Plasma to display deeper blacks. This adds to picture depth, scene detail, and colour richness. All these features cumulatively provide a good picture contrast. In case of LCD, back light leaks through LCD layer, thus it is difficult to get true blacks. If darkness measured is expressed in figures, the darkest image on Plasma TV is a fraction of a Candela. While in a LCD the brightness is as high as two to three Candelas. This is when viewed from front, if viewed from an angle the image deteriorates further.

Plasma TVs provide more natural colouration as compared to LCD. The mechanism used in LCD is complex. White colour is filtered through micro filters built in sub-pixels; in this process the colour picture looses its accuracy and vibrancy. LCD panels are more suited to brightly lit rooms, as they employ anti-glare technology and have bright screen.

The LCD technology is improving at very fast rate. The latest models use intelligent backlight units that give improved colour freedom. The backlight unit uses LED and colour field sequential technology to eliminate the filters in sub-pixels. This enhances the colour detail of the picture.

The contrast ratio of LCD is many times lower than that of Plasma’s. Samsung’s LCD has a contrast ratio of 4000:1, while plasma has 10,000:1. The Plasma promoter may brag about this feature, but in reality, even in pitch darkness, the human eye is not able to perceive any difference in the contrast ratio in the range 4000:1 to 10,000:1. So this feature should hardly matter. Again, only when viewed at an angle, these features get reduced.

The Plasma scores in rooms with lower to normal lighting, while LCD overwhelms in brightly lit rooms!

Viewing Angle: The safest distance one can sit away from centre without experiencing any deterioration of picture quality is said to be the viewing angle. Plasma TVs have a better viewing angle than that of LCD’s. More than 1000 off axis, picture quality deteriorates as a result of colour shifts, reduced contrasts and loss of black level intensity. Samsung and Sony have lately come out with LCD TV sets that employ Super Patterned Vertical Alignment (S-PVA) technology. This has boosted viewing angles from 1700 to 1780 range. Viewing angle will soon cease to be an issue of concern.

Viewing Distance: Plasma technology gives a uniform image when the viewer is far from the panel. To display the image, the pixels are lit or unlit. For brightness the pixels are lit frequently, but for dark shades it is lit less often. The human eye undergoes tremendous strain viewing the flickering images at frequencies of 85Hz, without the viewer being even aware of it. LCD pixels don’t flicker. A safe viewing distance would be to maintain at least nine feet! For a shorter viewing distance smaller sized LCD panels will be a good choice but then keep in mind the black level performance.

Picture Resolution: For the same screen size LCD supports a higher resolution than Plasma’s. A 5o inch Plasma achieves the same screen resolution as that of a 4o inch LCD that is 1366x768 pixels. Thus for a bigger screen LCD requires more pixels, hence the panel costs more.



Read on Kindle !