Painterly
Painterly offers some additional creative opportunities as it provides choices for background—assorted canvases, sandstone, papers—and the ability to stack multiple images as the painting source. A key requirement is restraint. The impact of Painterly comes partly from the “gaps” left by brushes allowing background to peek through; repeated brushing will simply result in the source image showing through as-is (depending on other chosen settings). There are 54 brushes in different groups—washes, sprays, smudges, pointilizers, swatches, stencils, bristles, swirls and basics. Each of these can be modified by tweaking parameters for size, rotation, spin, start angle, and more.
Another feature allows the selection of filters (posterise, sepia, grayscale, vibrancy, solarise, shift, twist, rake) and blend modes (mix, copy, overlay, luminosity colour, oft light, hard light, lighten, darken, difference). Combined with the different brushes and backgrounds, there is a huge range of potential effects that can be produced by Painterly.
There is some decent help available including videos. Judging by the results on tumblr, Painterly can produce some attractive results, but I can’t see myself taking the trouble to master the app.
oddrops 
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