By all accounts Red Dead Redemption 2 is one of the best looking, if not the best looking, games ever released on PlayStation 4 and Xbox One, and playing it at 4K resolution on PlayStation 4 Pro and Xbox One X makes it even better (in general). HDR support is, or should be, the icing on the cake.
HDR, or High-Dynamic-Range, is a technique that allows the reproduction of a greater dynamic range of luminosity than what is possible through standard techniques. HDR aims to present a similar range of luminance as experienced by the human eye, resulting in a superior image quality. Sadly though, if an analysis carried out by Digital Foundry is correct, this isn't quite the case in Red Dead Redemption 2, as the HDR support in the game appears hamstrung.
Digital Foundry took a look at Red Dead Redemption 2 HDR support on both PlayStation 4 and Xbox One and discovered that the game employs what they are calling "fake" HDR in place of true HDR.
The "fake" HDR in this case is basically transplanting the standard dynamic range image into an HDR container, which makes the source image an SDR one, resulting in little to no difference in image quality.
Getting a little more technical, Digital Foundry noted that Rockstar Games chose to expand the 8-bit SDR image to fill a 10-bit HDR container and that nothing is gained from this process. In some cases, image quality may actually suffer, as this technique makes white pixels show at their most bright value in HDR, which becomes a problem in menus.
Bad HDR implementation also leads to another issue, lack of luminance separation. Digital Foundry notes how not all white colored objects on screen have the same luminance, but the SDR source image is not able to carry enough information, resulting in objects producing the same light values as if HDR is not active.
These HDR issues aren't the only technical issues discovered in Red Dead Redemption 2 this week. Several users on our forums reported blurring issues while playing the game on PlayStation 4 Pro. Rockstar has since acknowledged the issues and is now working on a fix.
We don't know, however, if HDR issues will also be fixed as the developer has yet to make an official statement. We will keep you posted.