This article presents five good open source software fully compatible with Mac and PC. By definition, an open source software is available in source code and completely free to use.
The GNU Image Manipulation Program (or GIMP) is the free alternative to the excellent Photoshop. It is used to manipulate images, photos, graphics or even small GIF animations. Even if it is not as good as Photoshop, GIMP can do what most users will want to do with an image such as converting from almost any format to another, change dimensions, balance, luminosity, colorize, apply some interesting effets, combine images, etc. The interface of GIMP, very different from Photoshop, is a little strange at first but still easy enough. The more you use GIMP, the more you like it.
Audacity is a classic and free application to manipulate audio files. It can be used to record any audio on your computer (CD, microphone, Web music, etc.) and convert it to usual formats (WAV, MP3, AIFF, etc.). It also supports all sorts of audio edition, including multiple tracks mixing, noise removal, amplitude correction and built-in audio effects. It’s the ideal application to be creative with sounds. The Audacity free software is even good enough to be used by some professionals.
Inkscape is the free alternative to programs like Illustrator or CorelDraw. It is used to create or to modify vector graphics. Vector graphics are images that are not saved on a pixel or point by point basis. For example, to draw a line, a program like Inkscape just record the two end points. Vector graphics are usually smaller than usual images and always print perfectly. Inkscape supports many advanced SVG vector editing features such as shapes, markers, clones, alpha blending, patterns and grouping.
RSSOwl is used to organize news and information on the Web. It can combine the feeds of any RSS (Really Simple Syndication) site into a single and personalized interface. The RSSOwl can be the only program you use daily to read your favorite blogs and news.
Stellarium is a beautiful program to display and to learn the constellations. It shows the night’s sky as you would see it in the real life with your eyes or with binoculars. You can set your viewing location, date and time to get exactly the right sky. It’s really an impressive software to get for free. Just try it!