HDR is short for “High Dynamic Range,” and it’s the principal feature that sets many 4K displays and monitors apart. It’s a collection of new standards for displaying color and brightness information that allows the display to dynamically adjust its brightness at a very precise level, allowing for more accurate and vibrant displays.
Its current big challenge is that it’s going through a format war just like the old Beta/VHS or HD-DVD/Blu-Ray eras, with competing standards all scrambling to get the most support in displays, game consoles, movies, and software.
You can read about some of the different formats here.
Unlike 4K resolution itself, which can be tough to discern massive differences in depending on display distance and other factors, HDR is immediately obvious because it provides a dramatic amount of additional brightness and color detail. You can see this for yourself if you have an electronics store nearby. Dolby also has a tool that will simulate the differences on a standard display right here, if you scroll down a little bit.
