Film and digital-processors have a more limited range of light intensity sensing ability than the human eye. In most scenes;
if one exposes for shadow detail, highlights are over exposed; or if one exposes for the bright areas, detail is lost in the shadows.
Various techniques have evolved to overcome this limitation. Using neutral density filters over the bright areas, processing two
versions of the digital image, judicial use of the PhotoShop Shadow/Highlight tool, various masking techniques while processing,
and manual blending of bracketed images (images taken of the same scene with different camera setting in order to capture different
light levels in each) come to mind. Recently, however, software tools have become available that partially automate 'stacking'
multiple images. These tools and the technique are generally called HDR (High Dynamic Range). PhotoShop CS3 has HDR tools and Essential
HDR has just become available, but most folks are using PhotoMatix from
www.hdrsoft.com. Tutorials and discussions of
the technique can be found in the PhotoMatix application, on the "Tips" page at ShutterFreaks, on the NAPP (National Association of Photoshop Professionals) site and at the Digital Outback site.
Basic HDR processing uses multiple exposures of the same scene to allow photographers to capture the same range of light as is experienced by the human eye. Basic use of the tools is simple, produces images that are artifact free, and that capture a wider range of light than the previous, manual processes. Several examples are available here.
From the early use of the tools it was noticed that a too heavy hand on the various settings would produce 'strange', 'science fiction', 'other worldly' images. These were (and still are) decried, panned, and otherwise made fun of by a number of more traditional practicers of photography. However, it is also becoming increasingly obvious that with less restraint in the processing, detail not otherwise visible can be brought out, and that more luminous, intensely colored images may result. The term "HDRGrunge" seems to be considered an appropriate appellation for this more aggressive technique. Examples of this less restrictive process are available here. These results seem to be more acceptable to potential customers than to some photographers.
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