Local dimming on most LED TVs is not worth it because it is not really effective. As shown, only in full array LED TVs it is an improvement, but at the cost of a blooming effect.
Local dimming refers to the technology that changes the uniformity of the backlight in an LED screen. The television can change the luminosity of parts of the screen to better reflect the scene and create deeper blacks where necessary. It improves the weak black level of an LED TV, compared to the perfect blacks of a plasma.
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