GIMP 2.8.6

GIMP - A way to work with images. The program can cope with the challenges of creating graphics and logos, scaling, and cropping photos, coloring, combining images with layers, retouch and convert images into different formats. GIMP is one of the first applications of this class, which is distributed with open source software. Despite the fact that GIMP is free software, its capabilities almost as good as a similar product Adobe Photoshop.
In GIMP there is a pretty good set of color correction tools:

curves;
levels;
mixer channels;
posterization;
Hue-Saturation;
color balance;
brightness, contrast;
discoloration.
When using filters, tools, masks layers with different types of overlay (of 22) may be:
align littered the horizon;
to remove distortions introduced by the optics;
correct perspective;
carry out the cloning of objects in perspective;
crop the photo;
remove defects such as dust on the sensor (stamp, healing brush);
simulate the use of different color filters;
"Pull" the lost detail in shadows;
more.
Drawing:
several drawing tools;
freely scalable brushes;
support for graphics tablets;
Additional features for image correction throughout the paper are implemented in the form of screen filters. They are:
simulation of different types of color blindness (Protanopia, deyteronopiya, acyanoblepsia);
gamma correction;
correction of contrast;
color management.
Customizable interface:
floating palettes are easily grouped and regrouped;
possible to completely reconfigure keyboard shortcuts, mouse actions, and input devices like the Griffin Powermate;
Any menu can be turned into free floating window.

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