Sept. 2, 2012

How to batch-convert Sony ARW files using free tools

I love my Sony ASLR-350, but when shooting in raw format it uses the rather non-standard ARW format. Here’s how to convert a large set of these images to JPEG or PNG, using the free “ufraw” tool.

There are lots of tools around that say they can handle ARW files, but don’t be fooled. Many just take what seems to be an embedded low resolution thumbnail in the file and use that, giving you awful results.

In addition, many tools based on dcraw, the “standard” raw format conversion tool, don’t have the correct colour matrix set-up for your camera. As a result, the images come out looking strange (usually washed out and slightly green in my case).

Here’s what I use to convert a whole folder of images. It should work on Windows as well as Linux.

  • Install the free UFRaw tool.

  • On Linux, just use your package manager.

  • On Windows it is a little more complicated (see the “MS-Windows for dummies” section of the above link):

    First install the GIMP art package from this download page

    Install ufraw, and also download this DLL file from ufraw and put it in your ufraw’s “bin” directory. Use the “ufraw-batch” command line program in your Command Prompt (Windows) or Terminal (Linux).

Here’s an example:

ufraw-batch *.ARW --out-type=jpeg --compression=99

This should convert all the files in your current directory to high-quality JPEG files.

There are many different options available, for example, you can resize or crop the images. Use…

ufraw-batch --help

.. to list them all.

If you get error boxes about missing DLLs, see the above Windows install information. You need the “png” DLL file, plus the GTK DLL from Gimp’s install.