Krita is a KDE program for sketching and painting, offering an end-to-end solution for creating digital painting files from scratch by masters. The application provides users with both a classic and a new set of tools. Using Krita you are able to export your creations to PSD, PPM, PNG, JPEG, TIFF and PDF formats.
As is expected, Krita offers you both vector and raster tools to aid you with your work. You also get smudge, filter, hatching, texture, curve and spray brushes for which you can create custom profiles.
With Krita you can enjoy a very large number of filters amongst which levels, curves, glur, color to alpha, sharpen, sobel and unsharp are found.