LightZone is a free and open source professional grade photo editing application for Windows, MacOS and Linux. It comes with RAW image processing, Raw tone curve modification and editing options, batch processing of files and style filters. It is a non-destructive editor. It comes with relight, sharpen, gaussian blur, hue/saturation, color balance, white balance, black & white, noise reduction, clone, spot, red eyes tools and Alien Infrared, Skin Glow, Polarizer style effects.
Install LightZone on Ubuntu Linux
LightZone is available as a PPA for Ubuntu based Linux Distros. You can install it via the command line terminal application. Open terminal (ctrl+alt+t) and run below command to add its PPA on your system. You need to confirm the addition by pressing the Enter key during the installation process.
sudo add-apt-repository ppa:lightzone-team/lightzone
After that update its software source list using below command.
sudo apt-get update
Then install LightZone Photo Editing app via below command.
sudo apt install lightzone
You can open it via the applications menu or via below command in terminal.