High Dynamic Range imaging (HDR or HDRI) is a series of new photography technologies revolutionizing the quality of digital images. HDR is important because real world scenes contain light ranges usually exceeding 50,000:1 dynamic range. For the last thousand years, media has been limited to around 300:1 dynamic range. HDR imaging allows the photographer to replicate the tonal ranges available in real life.
Photographers and artists alike from El Greco, Monet, W. Eugene Smith and Ansel Adams have been trying to reproduce the tonal ranges of images. But, with the evolution of digital HDR an even greater range is possible without nearly the effort.
The transition to HDR imaging will affect all aspects of image creation, including capture, storage, editing and output.
The most common way for photographers to capture high dynamic range images is to merge multiple images into one to increase the dynamic range. This is done by taking multiple photographs at different exposures and merging them together to create a single high-dynamic range image. The product, HDRCapture simplifies this process by taking up to 15 exposures at the same time.
Traditional image storage formats such as JPEG and GIF provide only 8 bits per color channel and less possibility for tonal range, making them unsuitable for HDR photos. However, newer formats such as JPEG2000, RAW and PNG offer 16 bits per channel. HDRCapture stores images automatically in RAW format.
There are three main issues photographers must consider when editing images: representing brightness levels, creating graphical user interfaces for HDR editing and image size. Currently, it rendering images in a brightness level that is too great for the monitor to show is an unresolved issue at many times. Representing graphical images for editing can be difficult because the color ranges can go from 0 to several million making it difficult to graphically represent the middle ranges. HDR imaging also creates images up to four times larger then normal images. This makes editing very time consuming. Photographic technologies will have to be adopted to help deal with these issues.
Today, some digital displays have up to a 2,000:1 dynamic range. This trend of increasing dynamic range will continue.
Benefits and Uses of HDR Photography:
Today, the majority of HDR users are specialized professionals in film, animation and virtual reality industries. HDR imaging is very useful for turning graphic computer objects into images in real scenes. Creating panoramic images with wide dynamic ranges is another great use for HDR imaging. Another use of HDR imaging is in computer gaming. Recent computer graphics cards support HDR texture maps. As photographic technologies continue to improve, the greatest use for HDR imaging will most likely end up being consumer photography.
In the next decade, HDR imaging technology will revolutionize the way images are stored, manipulated, used, and displayed, forever.
Jason Dick is a technology expert and web author who works for eAcceleration Corporation in the Seattle, Washington area. He has been taking photographs for over 30 years and recently began writing articles for HDRCapture