Microsoft photo standard comes into focus
Published: 01 Aug 2007 08:09 BST
…for the technology. JPEG can describe each component of red, blue and green colour in a pixel with eight bits of data; because cameras typically shoot images with 12 bits of data, that means conversion to JPEG typically throws away information a photographer might want, such as details in shadowed faces or the subtle folds of white clothing. JPEG XR can store 16 or 32 bits of data per colour for each pixel.
Better compression technology, more details
Higher dynamic range will be important for image longevity, Rossi argued. Five or six years from now, "printers and displays will be well beyond what current JPEG technology is capable of accessing", he said.
Among the other advantages Microsoft touts:
- Compression technology that can record the same quality as traditional JPEG at half the file size or twice the quality at the same file size. In addition, unlike JPEG, the Microsoft format's encoding algorithm can preserve all the pixel data in what's called "lossless" compression.
- A broader colour gamut, permitting richer colours and better preservation as images are moved from camera to computer to printer.
- HD Photo images can be immense — 262 million pixels on an edge, or 68.6 terapixels total, as long as the compressed image doesn't exceed 32GB in size.
Many photographers today seeking to extract all the data from their cameras use "raw" formats, which capture image sensor information without in-camera processing such as colour balance, sharpening, noise reduction and compression into JPEG. Raw images, though, must be processed, often by hand, to convert them from usually proprietary formats into more easily viewed or printed formats such as JPEG or TIFF.
Microsoft, though, hopes JPEG XR will take away some of the need for raw images.
"You're giving people much of the capability of raw in a convenient file format," Rossi said. "On the ultra-high-end there might be still a preference to use raw," he added.
But the bigger challenge will be just getting mainstream photographers to use the format. Standardisation, along with the familiar JPEG terminology, could make that easier.
"The bigger challenge is going to be getting the equipment manufacturers to buy in and incorporate that compression standard into their hardware," Lee said. "Once you've got that hardware, you're well on your way to getting it at least adopted by some consumers."
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