It’s obvious from the minute you turn it on that the W905A is something special when it comes to producing deep and rich black levels, at least by LED TV standards. Sony's use of a VA panel helps, but it's more due to this model's edge light dimming feature. This changes the intensity of the backlight in different areas of the picture according to what's displayed onscreen.
Sometimes this type of dimming can produce pulsing effects or blocking, where some areas of the picture look unusually bright compared to other zones. Sony's system largely avoids these issues, as long as you keep the LED Dynamic Control setting on low, leaving you with more natural, high-contrast images instead. If you choose the more aggressive high setting, the dimming effects do become a bit more obvious and as a result more intrusive.
The TV also uses Sony's new Triluminos system to help it produce a wider colour gamut (i.e. more potential colours than usual). Essentially Sony has added some tiny quantum dots to the LEDs that help to boost the intensity of the set's colours. Standard LED TVs are already able to produce the full colour gamut used in broadcasts and Blu-rays, so it's hard to tell whether this is really a benefit.
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