Creating grunge paths from L-Systems

Inkscape allows you to generate an "L-System", which is basically a path that looks like a tree branch. This technique involves creating two of these paths and Intersecting them to create a random scatter. To generate an L-System go to [Effects -> Render -> L-system], the preset parameters should do for our example.

The image on the right shows what the resultant path looks like. The next step is to remove the stroke and add a background colour (red in this case). Notice that the background that gets created by this path is quite choppy and a bit random - much better than the manually-drawn paths we started with last time.

Next, copy the path, rotate and overlay the two copies on top of each other. There are some very aesthetic effects that can be made by combining the paths from L-Systems, I recommend that you experiment with them. For our purposes, though, we will apply an Intersection to the two paths while they are selected. Go to [Path -> Intersection] to apply this effect.

The picture to the right shows the resultant path.
The below picture shows different grunge paths that can be created from repeating this procedure with various degrees of displacement and rotation. Note that the second path from the right is not suitable for us, because it has a continuous pattern and doesn't look random enough.

Now it gets more interesting: because each of these grunge paths is a path, and they can be combined together, we can create higher order grimy paths. By applying the Intersection to pairs of these paths, we can get even more realistic grunge paths. The paths below are very sparse, but they look like the kind of damage that old photographs sustain when parts of them peel off.

We can now apply these new grunge brushes to our blue illustration, using the black background to make the white grunge paths visible while we work with them. The resultant illustration is shown to the right.

With even more brushes, and with "punching out" parts of the illustration and applying text, below is what the illustration looks like. The punch out effect was done by setting small circular paths on top of our illustration's paths and applying a Difference to them through [Path -> Difference].