In “Lightroom 4 beta now available” I mentioned that there is a new version of DNG on the way – DNG version 1.4.
(All versions of DNG remain valid, because old DNGs still have to be supported. The version number is written into each DNG file).
The main new features are summarised in this statement from Tom Hogarty (private correspondence):
- The ability to embed “Fast Load Data” that Adobe clients like Lightroom and Camera Raw will be using to load and display raw data much, much faster than waiting to read the entire file off of disk.
- Lossy Compression. The linear DNG data will be compressed providing the flexibility of raw with a significant reduction in file size. (Canon 7D files compress from 24MB to 6MB at full resolution).
- Lossy Compression with Downsampling. Lossy compressed DNG files can be reduced in resolution through a Lightroom export process. (There are a number of resolution decreasing options in the export dialog).
In the temporary absence of a published specification, here are some articles about the extra features in version 1.4:
- ChromaSoft: Lightroom’s new lossy DNG compression
- Adobe forums: Info on lossy DNG?
- The Luminous Landscape: lossy compression/resizing of raw data is coming to DNG ?
When the specification is available, I will update some of my DNG pages, for example: