HDR Photography of Products

摘要

First conceived in 1850, HDR, or high-dynamic-range, photography was introduced to Photoshop in Adobe Creative Suite 2 (Photoshop 9) as the Merge to HDR function. HDR has recently been incorporated into newer digital SLR cameras including the Pentax K and Sony Alpha line. HDR attempts to overcome the limited density ranges of photography and print as compared to the human eye. The technique involves combining multiple exposures that capture the highlight and shadow detail of high-contrast scenes, such as sunsets or brightly illuminated buildings against dark backgrounds. Online image galleries showcase HDR's aesthetic affects, in which photos often have a posterized or surrealistic appearance.This study was performed to determine the value of HDR photography in capturing low-key subjects, such as products for publication in magazines, catalogs, and newspapers-specifically, whether HDR would bring out more highlight and shadow detail without creating a posterized look. The authors compared conventional Camera Raw (DNG) captures with HDR captures made automatically by a Pentax K-r DSLR and manually in Photoshop. Captures were made on a studio copy stand with a 3M/Stouffer 12-step grayscale at the edge that was used to plot a tone reproduction curve comparing percent dot area in Photoshop with density of the original.HDR compressed the tone reproduction curve and also brought out more shadow contrast in low-key images. By subjectively evaluating proofs of conventional and HDR photos, the authors observed that HDR images can be captured of low-key subjects that have more detail but avoid a posterized look. However, HDR processing added about 22 sec. to each camera HDR photo and 48 sec. to each Photoshop HDR merge. In a 100-photo catalog scenario where each subject took 2 minutes to set up, HDR could add 10-25% to production time.