If an LCD monitor is trying to display black then the colour filter will be positioned such that as little light as possible (of any colour) from the backlight will get through. Most LCD monitors will do a reasonable job at this but the filter isn’t perfect and so the blacks may not appear as deep as they should. A definite strength of the VA panel is its efficiency at blocking light from the backlight when it’s not wanted. This gives deeper blacks and higher contrast ratios of around 2000:1 – 5000:1 with ‘dynamic contrast’ modes disabled – several times higher than that of the other LCD technologies. They are also less susceptible to ‘bleed’ or ‘clouding’ towards the edges of the screen which can make such screens good candidates for movie lovers and nice to use for general purpose work.
Another key advantage of VA is the improved viewing angles and colour reproduction compared to TN. The shift in colour across the screen and ‘off angle’ is less pronounced whilst shades can be produced with greater precision. In this respect they are better candidates for ‘colour critical work’ but they are not as strong in this area as the IPS or PLS technologies explored subsequently. There is generally a weakening of saturation when comparing a shade in the centre of the screen vs. that same shade towards the edges or bottom of the screen, from a normal viewing angle. There is also a shift in gamma that is most noticeable on greys but can also be observed on other shades, with said shade appearing to lighten or darken quite readily with even slight head movement.
It isn’t cost that has traditionally been the main weakness of the VA panel as they are typically fairly affordable with a good modern range available from companies such as Philips, Iiyama, BenQ and Samsung. The real weakness comes in their relatively low level of responsiveness with pixels transitioning from one state to another relatively slowly – leading to more pronounced blurring during fast motion. In some severe cases things can appear to ‘smear’ into a smoke-like trail as demonstrated in the video below, taken on a BenQ EW2430.