I prime MDF with BIN shellac based primer . Travis has Great vids on inkscape http://www.scrollsawgoodies.com/2009/09/making-scroll-saw-patterns-with-inkscape-l1/
I have learned a lot from them .
I design them. The program used is inkscape . When starting I ask color, theme and name. I make everyone different. I want to post more pictures in the gallery but it says I have exceed the limit?