Even formats that superficially appear to be straightforward can contain many separate pieces of information.

Here’s a Canon CR2 file courtesy of rawsamples.ch. Within it there is a main image, a full-size thumbnail, a small thumbnail, and some metadata. 

We’ve used our Bevara Accessor software to extract and decode these pieces. The main image is scaled to fit the page, but is not color-corrected; Bevara leaves color correction options open to the user.

Here’s another example, a Leica DNG image courtesy of rawsamples.ch. We see that it has a main image (again scaled to fit the page, but with no post-processing  or color correction) and also a small thumbnail.

As with many DNGs, this image also has metadata, some of which is:

Camera: Leica M8
DNG Version: 1.0.0.0
ISO speed: 160
Shutter: 11.3 sec
Focal length: 50.0 mm
Embedded ICC profile: no
Number of raw images: 1
Thumb size: 320 x 240
Full size: 3920 x 2638
Image size: 3920 x 2638
Output size: 3920 x 2638
Raw colors: 3
Filter pattern: RG/B
Daylight multipliers: 2.097456 0.946061 1.128163
Camera multipliers: 2.104980 1.000000 1.255310 0.000000

However, much of this metadata is contained in a MakerNote EXIF as opposed to other metadata storage options such as general tags and  XMP; in future posts we’ll discuss internal metadata storage options. 

This range of options raises a challenge in retrieving and preserving embedded metadata when preserving DNG-format images. If you’re relying on an asset management system that normalizes and migrates formats, you need to ensure that it takes into account any internal metadata forms as well as thumbnail versions that also  must be preserved.

Alternatively, Bevara’s preservation solution keeps all file pieces intact by packaging the original data file with an accessor. Read our whitepaper to learn more about our patented preservation process

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