This should've probably gone in Sketches & Experiments...sorry
It took just about a minute to do because I was lazy with it and just wanted to try this style
*shrug* To do this:
1. Fill a layer with gray.
2. Splotch some big dots of different shades (not complete black and white just a little off of the gray or a faded bit of other color).
3. Smooth it in a tiny bit (little circle motion with large smooth circle)
4. Click the blender tool & change the spacing to 10%
5. Mix the colors around in a way that looks like the image was dragged around and left little droppings of itself all around the layer.
6. Hold the dodge tool at one end and and swirl it around the screen quickly but not completely whitening the layer.
7. Do the same with the burn tool around the areas not splotched with lighter color from dodge.
8. Repeat 6 & 7 until you're happy with it.
:3
