This example takes advantage of both the extreme dynamic range that an HDR file is capable of holding and the ability to relight a scene based on the idea that an individual pixel can act as a light source.
The first image below is a freshly merged HDR file from 8 different exposures. The lighting scenario is quite extreme—very little light reaches the cave, while the outside is extremely bright due to an overcast sky. The monitor at this point is capable of showing only one or the other. No additional lights were placed inside the cave; we are working only with available light here.
Side note: the cave can be found in White Plains, NY near Silver Lake. It was possibly used as a bunker during the Revolutionary War and was later occupied by a hermit.
Here the exposure was brought down to reveal full detail in the trees and sky.
Staying in 32–bit several adjustments were made to bring out texture in the stone and keep detail and local contrast in the outside area. No camera either film or digital is capable of capturing such an extreme tonal range yet.
At this point the scene has great shape and dimension but lacks good quality light that would give it mood and create a pleasant atmosphere. Therefore we decided to spend the night and wait for the sky to go deep blue while the cave would be illuminated by warm light coming off of the fire (all done digitally, of course, through a series of tonal and color adjustments combined with very precise masking). Notice how parts of the stone in the bottom center of the frame, that were in the shadow before, are now fully lit. HDR files allow for such extreme changes without any loss in quality of tonal and color gradations as well as the underlying pixel structure. At this point all the work was completed in 32–bit and the file was converted to 16–bit mode.
For the final version several prehistoric cave paintings were added to the ceiling and parts of the wall, which now makes our cave 32,000 years old. Sparkles from the fire, which sits outside the frame, were created in Adobe After Effects using a particle generator. Rollover the final photograph to see the before and after versions; a larger image is available in the gallery section.
Once again, by staying and working in 32–bit mode allowed us to perform the kind of changes that would otherwise never be possible with regular images. This is a whole new approach to photography post–production.
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All photographs © DOT Editions, 2008. All Rights Reserved.