Well, if you want to make some simple rocky grunge brushes, it will take some practice and skill. It's not the easiest thing to do. But anyways, continuing on with the tutorial. Step 1 - Get a nice high quality photograph, it can be of anything, doesn't matter. I'm going to use this Billy Talent picture. Step 2 - Now, go to Image>Adjust>Threshold, you should get a window that looks like this. Step 3 - Screw around with the settings until you get a detailed black and white vectorish looking image. These shapes you see will be the main shape of the brush, the texture comes later. I'm going to use a setting of...30. Now my image looks like this. (Yours should look similar.) Step 4 - Now, we begin to take the square marquee selection tool, and we select areas we like. I am going to select a small portion of his shirt, down at the bottom. When we have an area we like selected, we press ctrl+c, to copy, and then we press ctrl+v. This copies the portion to a new layer. Step 5 - Now, we duplicate the new layer, and invert the colors by pressing ctrl+i. After we have done this, lower the second layers opacity to about, a 70%. This will be the textured part of the brush. Now, we take the eraser tool, and set the brush of it to the size 27 spatter brush. Put the erasers opacity to about a 20%, and begin brushing away on the inverted layer. DO NOT DRAG WHATEVER YOU DO! Click in various spots, but also, make sure to make it look textured and rocky, not blurry. Step 6 - Now we will see what mine looks like. See how it seems to be textured? Now, that was not as easy as placing a texture on it from a preset, but it looks a hell'of'alot better. Now we will merge the texture layer, and the base layer (the layer you copied from the photo). After you have done this, there should be 2 layers, the photo, and the brush layer. Click on the brush layer, and press ctrl+a, this selects the whole layer, then press ctrl+c. Now, go to file, new, and change the dimensions to about 400x500, this will be your "brush pallette". Click 'ok'. Now press ctrl+v, and erase any solid colors around the brush. Let me show you the areas I mean. The areas inside the red lines, are what I need to erase. Step 7 - After you have erased all the excess brushing, Go to image>adjust>Brightness and Contrast. Mess with the contrast to give it more of a rocky feel. This gives the texture more depth. Click okay when you have something you like. After, Get the square marquee selection tool, and outline the brush. Make sure your on the brush layer. Now, after outlining it, go to Edit>Define Brush, name it whatever you want. Now you have a new brush! Just continue doing this in various spots of the photo for different outcomes. Heres how mine turned out.
