The Source Code of the program is freely available on the download page @ Sourceforge. You can also find there previous releases.
Download, usage and study and modification of the Luminance’s code is free of charge (under the GPL License). However, a donation is highly appreciated, if you think we are making a good job. We commit to make it better every release.
Linux users should ask their vendors for a pre-packaged binary.
You can find the latest binaries for windows here:
Mac OS X
Mac users can download the latest version using this link:
[ Luminance 2.4.0 Mac OS X 10.8 & 10.9 (64 bit) ]
Those still using Mac OS X 10.5 Leopard (or later) can still download the old versions:
Unlike older versions, this one does not require to download and install any external dependency because they are already deployed inside the dmg file.
Information about older versions can be found here.