HDR: In image processing, computer graphics, and photography, high dynamic range imaging (HDRI or just HDR) is a set of techniques that allows a greater dynamic range of luminances between light and dark areas of a scene than normal digital imaging techniques. The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to shadows.
This is done by combining multiple images with different exposure levels in to a single image that contains all the exposure information of the selected shots. Photomatix and Photoshop are two applications that can render HDR images.
For even more info go HERE.
Duotone: Duotone is a halftone reproduction of an image using the superimposition of a contrasty black halftone over a one color halftone. This is most often used to bring out middle tones and highlights of an image. The most common colors used are blue, yellow, browns and reds.
Now that you have been enlightened, informed, educated, wised up, instructed, knowing what's what and here by knowledgeable: here is an image that incorporates HDR to B&W to Duotone. All three are strong images types in their own right but together, make some rather awesome imagery.
HDR is a fairly new style that gets a lot of press and is about 50/50 on the like/dislaike scale. Let me know if you like or dislike HDR images and why?
For more images in the HDR style, you can visit my Flickr area HDR: My Way for more examples to better base your opinion from.
This shot was taken aboard the M.S. Paradise Carnival cruise liner while out to see en route to Mexico with a Canon 5D and 28-135 IS USM lens, tripod mounted.