DNG is an openly documented RAW format, while proprietary RAW files such as CR3, NEF or ARW are defined by each camera maker. For long-term archiving, DNG is the more future-friendly container, but keeping the original files alongside it is the most careful approach. Either choice works if you back up properly and keep your files organized.
What Each Format Is
A proprietary RAW file holds the unprocessed sensor data in a layout the camera maker designed. Software support depends on the maker and on the editing program continuing to read that layout. DNG, short for Digital Negative, was created by Adobe as a public specification, and many programs and some cameras can read or write it.
Key Differences for Archiving
| Factor | DNG | Proprietary RAW |
|---|---|---|
| Specification | Publicly documented | Defined by the maker |
| Software support | Broad across editors | Depends on the maker and the editor |
| Metadata | Can be stored inside the file | Often paired with a separate sidecar file |
| Original data | May lose some maker-specific details in conversion | Everything the camera wrote is kept |
| File size | Often similar or somewhat smaller with lossless compression | Varies by camera and setting |
Reasons to Choose DNG
- A public specification makes it easier for future software to open the files.
- Edits and keywords can live in the file instead of a separate sidecar.
- Optional embedded checksums let you detect file damage during later checks.
Reasons to Keep Proprietary RAW
- You hold exactly what the camera recorded, with no conversion step.
- Some maker-specific tools and color profiles work best with the original format.
- Skipping conversion saves time on large shoots.
A Practical Archive Workflow
- Copy the originals from the card to two separate drives as soon as you finish shooting.
- Decide whether to convert to DNG, and if you do, keep the originals until you have confirmed the converted files open correctly.
- Use a clear folder structure, such as year then date then event, and keep names consistent.
- Store one copy offsite or in cloud storage.
- Every year or so, open a sample of old files and copy the archive to fresh media when drives age.
FAQ
Does converting to DNG reduce image quality?
The sensor data is kept in a lossless conversion, but some programs may not carry over every maker-specific detail. Check your converter’s options and keep the originals if that matters to you.
Will proprietary RAW files stop opening someday?
Popular formats are supported for a long time, and open-source tools exist for many of them. Still, no format is guaranteed forever, which is why regular copies matter more than the format itself.
The Short Version
DNG offers an open specification and in-file metadata, which suits long-term storage. Proprietary RAW keeps everything the camera wrote. For the most careful approach, keep your originals, add DNG copies if you like, and maintain several backups.
