I'm performing a simple transformation of a batch of files taken in RAW mode with an Olympus OM-D EM1 camera (extension is "ORF") to jpeg using ImageMagick. When I run the command, mogrify -format jpg *.ORF it produces a handy pile of jpeg files, however the resulting files are extremely dark, in some cases unusable. I'm aware that the RAW files have a much richer set of data about light and that this conversion is likely discarding that data. Is there a simple way to get around this issue? I've tried working with -brightness-contrast brightness{+30} and this really just produces washed out images which are inferior to the RAW files when I can view them as a preview. My ultimate goal is to produce lower resolution files which are smaller and can be viewed on a mobile phone, whilst keeping all the RAW files.

1 Answer 1


This is expected, they are RAW files and need to be developed, imagemagick is not the right tool for it.

But as your goal is to just get smaller preview images, you can simply extract the internal JPEG preview saved with the camera settings. They can be easily extracted using e.g. dcraw:

dcraw -e *.ORF

or ufraw:

ufraw-batch --embedded-image *.ORF

This will create additional files *.thumb.jpg or similar next to your ORF files.

For more options, see also

To really convert your RAW images (=develop), you could also use dcraw or ufraw, or some GUI tools like darktable or rawtherapee, but for your task this is not needed. imagemagick is afaik not the right tool.

  • That was the ticket. Exactly what I was looking for. Totally take on board your point re: the need for raw image processing, and I usually use darktable for this, but nonetheless surprising that the conversion was so dramatic! Thanks for this. Oct 29, 2020 at 15:25

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