All hail! I've been working hard lately on a number of freelance projects as well as making headway for the Arcane Knights video game. All my output for these projects is executed in open source software, and I am but one of a growing crowd of artists choosing this path as opposed to using proprietary programs. I would like to speak briefly about my work flow for a typical project and what would be analogs in the proprietary world.
For most illustrations I start out by using MyPaint, which is somewhat equivalent to Autodesk's Sketchbook Pro or Corel's Painter. For a lot of digital artists, the process begins and ends with Photoshop, which is an admittedly badass program, but I prefer MyPaint for its highly flexible brush engine and infinite canvas. It supports decent layer functions, outputs to a growing variety of formats (.png - solid and alpha, .jpg, .tiff, .bmp, and the powerful .ora), and eliminates distractions from the task at hand - creating. The hotkey system is a cinch, customizable, and can be assigned to buttons on your Wacom tablet or a number of supported off-brand tablets. Needless to say, I rely on this smooth program as my primary.
For image editing, I will bounce my paintings into the GIMP. Thousands of folks have posted useful blog entries about various flavors of the GIMP in the past, so I don't intend to speak too much here. Its the Photoshop equivalent in the open source world, and it stands out more and more as newer versions of P-shop slowly remove various functionalities that were once assumed to be universal and basic components. Moreover, you can download a plug-in for GIMP to support the .ora format native to MyPaint, which is HUGE in terms of manipulating heavily layered paintings generated in other open source programs in a standardized format.
Third, I use Inkscape for my vector work. Tracing raster images, building clean and/or complex layouts and logos, or designing and outputting web graphics are the key tasks for which I deploy Inkscape the most. It has a little way to go before it catches up to Adobe Illustrator, but it supports layers, swatches, channels, tight node editing, and so forth - and it plays well with tablets to boot. You can output to darn near any file type imaginable, including a lot that I've never heard of, and I've had considerable success importing .ill files from Illustrator!
If you have any suggestions or ideas on 2D work flow in open source software, feel free to email me or comment below. Meanwhile, I've assembled a two-part tutorial on Youtube detailing some speed painting and rendering techniques, please check them out! Audio was recorded using Audacity and video was recorded using RecordMyDesktop and edited with OpenShot. Cheers!
Speed Painting Demo - Part 1
Speed Painting Demo - Part 2