DxO PureRAW 2: Extract original RAWs from RAW files?


DxO PureRAW 2 converts original RAW files into linear DNG files.

The DNG created by PureRAW 2 has more than double the file size compared to the original RAW file. Example from my test:

  • original RAW: 18 MB
  • PureRAW DNG: 43 MB

Some reviewers state that the original RAW file is embedded within the DNG from PureRAW. This is technically possible, but:

I tried to “extract” the original RAWs from the PureRAW-DNG files with Adobe DNG Converter 14.2 (current version, click “Extract” at bottom). But the DNG Converter does nothing, it quits the job, it does NOT extract the original RAWs.

So it seems I cannot extract the originals any more. And if I want to keep the original data, I end up with:

  • original RAW, 18 MB, and
  • PureRAW DNG, 43 MB

Is that really the case?

Thanks for your insights!

Welcome to the forum, @Henrik

DNG output contains a demosaiced image without additionally storing the original RAW image. This is why the original RAW image cannot be extracted from DPR’s output DNG files.

Instead of containing information in R, G, G, B (for four pixels), the output file contains RGB, RGB, RGB, RGB, which does indeed increase file size considerably (three times minus compression).

Read more about it here:

Simple answer: Yes!

Can I ask why you are using PureRAW rather than using PhotoLab, which will fully process your RAW images and only export images when you need to use them?

I fear so.

Did you get any useful help from the support people ?

Joanna, thanks, i agree that using PhotoLab would avoid creating linear DNGs with their disc space requirements. I hadn’t considered that so far. But some people might want

  • the DxO DeepPrime image quality
  • the workflow convenience some other program
    and then PureRAW seems to be the solution - after all, DxO seems to think so too.

Platypus, thanks for good info and links!

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Be aware that if you use the dng converter from adobe you can set the size of the embedded jpg too. Nikon uses a full size jpg so if you use Nikon and want to compare that with a dng from the adobe dng converter be aware of that size.