Acer Predator XB321HK 32″ 4K G-SYNC Monitor Review
Panel Backlight Bleed
An LCD or LCD LED-based monitor relies upon either one or multiple sources of light to illuminate the liquid crystals so as to create a visible image. In a perfect world, all the light would either go through the open crystals or be reflected back into the interior of the display via the closed crystals. Due to the manufacturing process, most monitors exhibit light leakage around the edges of the monitor. This issue is called ‘backlight bleed’ and can drastically lower the contrast near these affected areas. This causes colors to have a washed out appearance, with blacks appearing to be more gray that black. Ideally, a monitor should have zero bleeding, but if the amount is judged to be fairly minor we will consider it to be adequate.
To determine the amount of backlight bleed a given sample exhibits, we have placed the monitor in a completely dark room and have taken a series of pictures of the monitor using a Nikon D810 with a 24-70 F2.8E VR lens. In between each shot the ISO is raised by one stop until a picture is captured that shows the amount of backlight bleed occurring.
We must admit to being impressed with the amount of backlight bleed our XB321Hk sample exhibited. Basically, the left side shows a small amount of bleeding along the edge and a minor amount in the bottom left corner. On the other hand, the top, bottom and right side basically had zero backlight bleed. To put this amount of bleed in perspective, we had to go all the way to ISO 4,800 before we were able to obtain an image that was anything other than black. Very impressive!
Gamma correction is one of the hardest terms to explain. However, for our purposes, the gamma correction of any electronics device is how bright or dark an image will be displayed on a screen.
All PC devices now use 2.20 gamma as the default. Any variance from this will result in an image being either underexposed – which will create black crush and reduced shadow detail – or washed out with overexposed highlights level detail.
While 2.20 is the gold standard, a minor deviation of 0.10 will in all likelihood never be noticed by anyone other than professional photographers. Higher levels of deflection however will be noticed by just about everyone.
Even though 2.21 is technically not perfection, it is pretty damn close. So close that it does fall within the margin of error of our testing equipment. Brilliant stuff and better than every other Acer monitor that we have tested, except the equally competent XB270HU.