LumaTone is a small (batch) utility I created with PureBasic to apply a color scheme to images based on the luma value of each pixel.
Things you can do with it are for example to create a duotone or sepia effect.
It's mainly targeted at working with jpeg photos but you can use for example png as well.
Be ware though that png encoding can be very slow for large images.
The utility is cross platform and portable meaning that user presets are stored in a small .dat file in the same folder as the app itself and nothing is installed on the computer.
In fact, if you place multiple OS versions in the same folder on a usb stick, you should be able to use it where you go.
The OSX version is not signed so you have to right-click the file the first time to give permission to open it.
I'm not very familiar with Linux so I can only hope it works on distributions other than the one I used to create it.
A thank you to J. Baker for creating the app icon and to Keya for solving the problems with libjpeg-turbo on Windows.
Hope you enjoy it

Examples
Input

Output



Input

Output



Screenshot (Windows 10)

Current build :
LumaTone_1_1_1_OSX_x64.zip
LumaTone_1_1_1_Windows_x86.zip
LumaTone_1_1_1_Linux_x64.zip
Previous build :
LumaTone_1_1_0_OSX_x64.zip
LumaTone_1_1_0_Windows_x86.zip
LumaTone_1_1_0_Linux_x64.zip
Changelog :
v1.1.1 Added a slider to control the brightness of source images and added a click to refresh for the large preview window.
v1.1.0 Added grabbing screen colors ( [ctrl] + [G] ) and changed png encoder
v1.0.5 Added full size preview window ( open with [ctrl] + [P] )
v1.0.0 Initial release