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"Inspired by the article "18+ Sources of Inspiration from Coffee, Ink, Blood and other Stains," by Steven Snell, I decided to show my personal way of creating stain based designs in Photoshop. In this tutorial, we'll grab a picture, apply several filters to it and obtain a monochromatic stain, which combined with stain brushes and a texture will transform into an eye-catching grunge result. Let's get it started!" Alvaro Guzman
Here is a link to the written version of the tutorial How to Create a Grunge Style Illustration with Stains and the video version is below.