darktable runs on GNU/Linux / GNOME, Mac OS X / macports and Solaris 11 / GNOME.
Fully non-destructive editing.
All darktable core functions operate on 4×32-bit floating point pixel buffers, enabling SSE instructions for speedups. It offers GPU acceleration via OpenCL (runtime detection and enabling) and has built-in ICC profile support: sRGB, Adobe RGB, XYZ and linear RGB.
A collect module allows you to execute flexible database queries, search your images by tags, image rating (stars), color labels and many more. Filtering and sorting your collections within the base query or simple tagging by related tags are useful tools in your every-day photo workflow.
Import a variety of standard, raw and high dynamic range image formats (e.g. jpg, cr2, hdr, pfm, .. ).
darktable has a zero-latency fullscreen, zoomable user interface through multi-level software caches.
darktable currently comes with 18 translations: Albanian, Catalan, simplified Chinese, Czech, Dutch, Finnish, French, Galician, German, Italian, Japanese, Polish, Romanian, Russian, Spanish, Swedish, Ukrainian and Thai.
The powerful export system supports Picasa webalbum, flickr upload, disk storage, 1:1 copy, email attachments and can generate a simple html-based web gallery. darktable allows you to export to low dynamic range (JPEG, PNG, TIFF), 16-bit (PPM, TIFF), or linear high dynamic range (PFM, EXR) images.
darktable uses both XMP sidecar files as well as its fast database for saving metadata and processing settings. All Exif data is read and written using libexiv2.
Install Darktable in ubuntu
Open the terminal and run the following commands
sudo add-apt-repository ppa:pmjdebruijn/darktable-release
sudo apt-get update
sudo apt-get install darktable