This effect was generated in Filter Forge, a Photoshop plugin that allows you to create your own filters.
This filter emulates drawing precise lines with a fine tip pen. Color and some color controls were added for some more versatility.
If the lines degrade to squares try adjusting the Size/Pixel slider. Try settings of 400, 600, 800 or 1200, (or multiples of 400), this seems to correct the problem.
photoart, artistic, drawing, pen and ink, line, tech
This filter has earned its author one of our rewards. They are given to the authors of popular filters and include a free copy of Filter Forge.