This program uses the HDR (High Dynamic Range) technique, that consists in merging several photos of the same thing with different exposure ranges to create a unique photographs with a color depth that is much more impressive.
FDRTools is very easy to use, all you have to do is open the photos that you want to use, whether RAW, JPEG, TIFF, Radiance RGBE and OpenEXR, to be able to see the different color levels that each of the images has. Once they are open, you'll be able to select if a snap is used or not, with the possibility to preview each change.
Furthermore, FDRTools allows the user to change the color and tone parameters to modify the resulting images, and it allows us to export it as Radiance RGBE, OpenEXR, TIFF, PNG, PPM, BMP or JPEG.
Therefore, if you want to improve the final quality of your digital photos, take the same pics with different exposures and use FDRTools to create a high dynamic range image.