What exactly is HDR for a PC Gamer?

[NeedHelpBuildingPC]

So with the release of the PS4 Pro, a lot of people are talking about HDR.
After ages of googling and searching many sites I have come here looking for some details on this technology. At first I though HDR was something TV manufacturers were making TV's with, however after finding a post on Steam talking about how PC has had "HDR for ages," i'm not to sure. Does this mean it is a visual effect rather than something that is built into the display? Does that also mean that I can run HDR on my existing display without buying an entirely new one? Or do you have to have a specific display for it to work? Is HDR more demanding / will it drop more frames than a normal display. I have found a lot explaining what HDR does in terms of photography, but very little in terms of gaming. I am very confused about this and, what it means for PC gamers. Any explanation on help would be greatly appreciated.

 

[dudio]

Check this:
https://en.wikipedia.org/wiki/High-dynamic-range_rendering

It is a visual effect

 

[Wes006]

High-dynamic range (HDR) is a term that's used to describe an expanded range of luminosity in digital imagery. This is fundamentally achieved by supporting 10 bits per channel (1024 different values per channel, 3 channels total) for total of 1,073,741,824 values (or colors). There are also techniques known as "Alpha Compositing", aka the Alpha Channel (e.g. https://en.wikipedia.org/wiki/Alpha_compositing). Instead of being limited to 256 gradations or levels of light, as is the case with 8 bits per channel, there are 1024. You also get tighter conformity to the Rec. 2020 color space (e.g. https://en.wikipedia.org/wiki/Rec._2020) for much greater color accuracy. One of the perks of having higher color accuracy is the reduction of "color banding" (e.g. https://en.wikipedia.org/wiki/Colour_banding).

 

[NeedHelpBuildingPC]

Check this:
https://en.wikipedia.org/wiki/High-dynamic-range_rendering

It is a visual effect

So this means that I don't have to purchase a new display in order to utilise this effect?

 

[Wes006]

It is not a visual effect. Your display device (monitor, TV etc.) has to support 10 bits per channel video as a prerequisite. The term "HDR" is just easier for marketing purposes, instead of going into technical detail of how it's achieved.