Adobe Updates DNG Specification, Releases Vista Codec
By
Mike Pasini, The Imaging Resource
(Tuesday, May 13, 2008 - 11:25 EDT)
Two new features added to DNG, which has been submitted to ISO, and a 32-bit Vista codec release candidate
Adobe has released version 1.2.0.0 of the Digital Negative Specification, the first revision in the last three years.
The update brings two new features to DNG: it formalizes the concept of a camera profile and adds a metdata tag to validate image data.
By defining a camera profile and embedding multiple camera profiles in a single DNG file, the company hopes to provide something like ICC profiles for Raw data.
The metadata tag to validate image data is simply a field to indicate a hash of the raw data in the file. A corrupted file would not calculate the same hash value as the original image data. This ensures that any potential change to the original Raw image data from disk corruption or an I/O error would be immediately detected.
DNG edits are recorded in the file as metadata, providing a recipe for changes to the original Raw data, and thus do not alter the captured image directly.
The company also recently announced that the DNG format specification has been submitted to ISO as a vendor-independent standard.
Vista Code
Adobe has also released a 32-bit Codec for Windows Vista users as a "release candidate" on Adobe labs. In his Lightroom Journal blog, Tom Hogarty explained, "A release candidate is a version of the technology that is nearly complete but we would like the community's help in ensuring compatibility across a wide variety of hardware and software configurations."
The new codec makes it possible to view DNG files within 32-bit Vista.
The DNG codec is not compatible with 64-bit Vista, although the company is "working with Microsoft to add support in the future," according to Hogarty. Several other current codecs are not 64-bit either, he pointed out, including Canon and Nikon codecs. But Lightroom 2 is already 64-bit and the next version of Photoshop will be 64-bit native on the Windows platform.
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