RawTherapee

RAW-formatted photographs are much higher quality than any other format, but they are almost always incompatible with image editors. RawTherapee is an editor that addresses this problem.

This tool is compatible with the majority of formats used by DSLR cameras (like NEF, DNG, and others), and is also capable of processing common formats like JPG and TIFF. The way RawTherapee works - and even the way it looks - may remind you of Adobe Photoshop Lightroom, and although its effects are applied a little slowly, the results are quite gratifying.

The tools included in this program are basic photo processing stuff, like brilliance, contrast, levels, colors, sharpness, and noise, as well as cropping, resizing, history of changes, and photo metadata.

It's easy to use; just direct it to your file explorer and open the folder that you need. Once there, you will view all of your images, and can then make use of RawTherapee's scoring and classification system.

With this program, you can recover a photograph with little light by using a mixture of curves, smooth the skin of a portrait subject, clean up a photo's coloring, and even eliminate spots, among many other examples.