CoolTechZone.com has posted a HDR (High Dynamic Range) Technology Overview

We've all played Half-Life and it's sequel Half-Life 2. The difference between the two games, in terms of graphics, is tremendous, and now Valve has gone ahead and updated the gaming engine to give you a level of detail and realism that you thought wouldn't be possible until perhaps the next round of game releases.

HDR (High Dynamic Range) Technology Overview