XDepth brings High Dynamic Range capability to JPEG
San Rafael de Escazu (Costa Rica) – It appears that a small software company from Costa Rica has made huge step towards next-generation imaging, by adding High Dynamic Range (HDR) support to the good old JPG format, while keeping the updated format backwards compatible with 8- to 24-bit JPEG editors and viewers.
HDR is believed to bring the next big innovation wave to digital photography: Merging digital pictures with different exposure settings into one with the purpose of achieving more depth, detail and even surrealistic effects is already supported in image editing applications such as Photoshop. We also hear that a new generation of digital cameras, which will be taking the same picture at different exposure settings at the same time, will offer an automated HDR feature in the not too distant future.
The unanswered question, however, has been which format these HDR images will use. Since these images reveal their fascination in 32-bit color, the format range typically has been limited to space hungry formats such as TIFF, which consume somewhere between 75 and 100 MB for a six megapixel 32-bit image. Microsoft has come up with a much more efficient solution called HD Photo, which we found to cut about two thirds of the file size without visible quality deterioration. The problem with HD Photo really is that it is a new image format and we have learned over the years how difficult it is to establish such a new format, even for a company like Microsoft.
Costa Rica-based Trellis Management claims that it has found a solution for this problem and is first to apparently have succeeded in extended the JPG format with HDR capability. Available at this time as a Photoshop and Internet Explorer plug-in, XDepth enables users to create, edit, save and view JPEG images not just in 8-bit to 24-bit, but in 32-bit HDR format, while offering common HDR adjustment. The beauty of this solution is that these 32-bit images remain backwards compatible, which means that browsers still can display them as regular JPEGs and other image editing software such as Corel’s Photo Paint can still open and edit them, albeit not in HDR format. To see the HDR image, however, users will need the XDepth plug-ins, which are currently offered as free downloads.
We will closely examine the capabilities of this new format and have limited our test to one image sample so far. Our test image was 1634 KB in uncompressed TIFF format and was reduced to 17 KB in JPEG format (50% compression). The conversion to a 32-bit JPEG HDR resulted with 10% compression in a file size of 35 KB, whereas the lossless file ended up at 76 KB. The comparing lossless Microsoft HD format was 282 KB. At least in this one sample, we were not able to see any visible differences in quality between the HDR JPEG and the HD Photo versions of the image.