The HDR Gene Pool

High-dynamic range (HDR) is a technique of rendering an image that dates back more than 100 years old, yet it wasn't until it took hold in gaming that I came to understand and care about it.

In gaming, high-dynamic range is a method of altering the lighting of a 3D environment in such a way that the final image you see on your screen more closely mimics the way your eyes interpret light. The easy way to make sense of my mumbo-jumbo is this: when you are in a dark room (say, a movie theater) for some period of time, your eyes eventually adjust to the low-contrast of the dark room. Suddenly walking out of this theater and into daylight will flood your eyes with light, causing everything to seem over-saturated with light and color for a few moments until your eyes adjust to the new brightness. HDR in gaming simulates this. The effect is subtle in most games, but noticeable enough to make a difference in realism.

The original form of HDR, however, was used in still images - photographs.

By taking photographs of the same scene multiple times with different exposures of contrast, then smashing them together (and by following certain parameters), pictures could display all levels of contrasts that is available via the visible light spectrum, but not available to humans, as our eyes are designed to adjust to a level of contrast that is most comfortable and easiest for our brains to interpret. While a little odd-looking at first, photographs produced via HDR can typically look stunning, either crystal-clear beyond the resolution of traditional photographs or psychodelic and trippy against a spectrum of color, depending on a lot of variables in the creation process.

But alas, I bring you through all this techno-babble because there is an excellent group on Flickr dedicated to displaying HDR images, and I highly recommend you check it out. There are years worth of images and a wide-range of HDR techniques on display, so head over there now. I posted the link on my QuickLinks page page, so the link will always be available there too.

Flickr: HDR Pool