Darkr is described as 'is the darkroom-inspired app that lets you develop photos similar to how you would in a real dark room' and is a Image Editor in the Photos & Graphics category. There are more than 25 alternatives to Darkr for a variety of platforms, including Windows, Mac, Linux, iPhone and iPad. The best alternative is Paint.NET. It's not free, so if you're looking for a free alternative, you could try digiKam or darktable. Other great apps like Darkr are Adobe Lightroom (Paid), RawTherapee (Free, Open Source), ACDSee Photo Studio (Paid) and Polarr (Freemium).
digiKam is an advanced digital photo management application which makes importing and organizing digital photos a "snap". The photos are organized in albums which can be sorted chronologically, by folder layout or by custom collections.
darktable is a virtual lighttable and darkroom for photographers: it manages your digital negatives in a database and lets you view them through a zoomable lighttable. it also enables you to develop raw images and enhance them.
ACDSee is a complex, multi-purpose application that serves for viewing, organizing and editing digital photos. Furthermore, images can be shared on social websites or your own space on the developer’s website.
From high-precision light and color tools, to advanced clarity and dehaze settings, to the ability to create and save your own filters. Polarr is the ideal photo editor for bloggers, students, and photo professionals alike.
PhotoFiltre 7 is a complete image retouching program. It allows you to do simple or advanced
adjustments to an image and apply a vast range of filters on it. It is simple and intuitive to use, and
has an easy learning curve.