Adobe attempts to unify image formats

With a new image format, Adobe believes it can improve the quality and longevity of digital photographs -- but the software maker faces serious challenges.

Adobe promotes its Digital Negative (DNG) format as a replacement for the profusion of useful -- but proprietary -- image formats of today's high-end cameras. The company believes the industry and consumers would benefit from a unified format.

Now Adobe's challenge is to build consumer demand and find industry allies. So far, only a handful of cameras support the technology, it doesn't ease some of the difficulties of the proprietary formats, and it's not a neutral industry standard.

But the company is patient. "When we announced DNG two years ago, we said that it would be a slow road to adoption. We already have a variety of cameras at different price points supporting the format natively. That's very good progress," said Tom Hogarty, Adobe's digital imaging product manager.

DNG is the byproduct of the ability of higher-end cameras to store data in their own 'raw' formats. While most cameras convert their sensor data into images in the JPEG format, raw formats record the unprocessed data. Photographers must use software to process raw into more convenient formats such as JPEG (Joint Photographic Experts Group) or TIFF (Tagged Image File Format).

All digital SLR cameras and several compact models can produce raw images, and enthusiasts and professional photographers have rapidly embraced the technology to gain fine lighting and tonal control for their photos.

A raw deal
Most consumers are happy with JPEG, but raw formats offer considerable advantages.

One is superior dynamic range -- the ability to record subtler differences in shading. For each pixel of an image, JPEG stores 8 bits of data describing the amount of red, green and blue light. Raw images record between 12 and 16 bits per colour, so images have finer gradations in light levels.

That means a JPEG photo of a skier might show a featureless wash of white snow, where a raw image would let a photographer emphasise the snow's subtle shadows.

Raw images also let photographers adjust white balance, the varying proportion of colours found in sunlight, incandescent light, fluorescent light and other conditions. With JPEG, photographers rely on the camera's best guess about the lighting conditions.

"I shoot 95 per cent nature images, and conditions and light are constantly changing. Shooting raw gives me so many opportunities to make adjustments before I start the actual editing process," said Ray Barlow, a hobbyist nature photographer in Grimsby, Ontario.

But raw poses a problem for companies like Adobe, whose bread-and-butter business includes image-editing software such as Photoshop, Photoshop Elements and Photoshop Lightroom. They must write new software to support each new camera model's raw image variation.

"This raw format Tower of Babel is going to explode," said Dave Story, Adobe's vice president of digital-imaging product development, who argues. Raw support is a challenge today, but Story argues it's only going to get worse. That's because more camera manufactures will add raw support, to entice consumers displeased that more megapixels from their camera hasn't meant higher-quality images.

The second major motivation for DNG is to ensure raw images will have an archival standard that endures even if camera makers' raw-processing software doesn't work on future computers, or if those manufacturers themselves go out of business.

"There's basically a new format for every single camera model. In 5, 10 or 15 years, how easy will it be to find software that supports those proprietary file formats?" Hogarty asked. "Is there a need for a unique format? Wouldn't it be better if we stored information in a common way?"

That argument appeals to some photographers. "It is a great idea to have a standard for raw images, because who knows where photography will go in the future?" said Holly Yurchison, a photographer who recently began selling family portraits.

Ken Milburn, author of Digital Photography Expert Techniques, likes DNG's longevity. "It makes sense to convert whatever you get out of your camera into DNG just for archival purposes," Milburn said. (Adobe offers a free tool to convert images into DNG.)

Not so fast
Standardising raw isn't that simple, though. Adobe's DNG plan initially resonated with Doug Meisner, senior product manager of Paint Shop Pro Photo at software maker Corel, who doesn't relish the prospect of decoding dozens of cameras' raw formats. But he became disillusioned.