Can't say enough times that you have to make sure to double and triple check all traces when doing this.
I don't do PCB myself but I know if I did, this is how I would want them to look :)
I made a tutorial here:
http://djoman.dyndns.org/diystompboxes/pcb-blur/
Neat photo retouching trick to get teardrops on the pad/trace intersections.
The blending of the junctions of the pads and traces is know in the PCB biz as "teardropping" and the advanced PCB packages have this as an automatic option.
Nice trick. Less "etchant traps" (etchant tangling into sharp corners causing more corrosion than intented, or alternatively etchant not flowing freely into every section).
It's almost the same thing as a median filter which most image editors include.
However, the median filter looks like it's built using a box blur algorithm rather than the gaussian algorithm (gaussian which results in smoother bends)
Would be cool to get something like this going on though:
http://www.aronnelson.com/gallery/main.php/v/DRAGONFLY-LAYOUTS_0/album18/FUZZ+PCB/VINTAGE+STYLE+FUZZ+FACE+-+SILICON_001.GIF.html
Might give that a try one day.
That's a cool trick. I like the look of vintage PCBs, more like art than the new ones are.
There is a great open source raster to vector program called potrace to do exactly this;
http://potrace.sourceforge.net
For Linux users there is also a gui;
http://potracegui.sourceforge.net
For Ubuntu/Debian users you can just; sudo apt-get install potracegui
Nice find! Gonna try that.