I did do some post production work on this scan from my sketchbook – I made the image grayscale then reversed the colours, making the image white on black. The letters were also generated on the computer then printed out, cut up and glued into my sketchbook.
The font I have thoroughly abused is Futura Book. Paul Renner is probably spinning in his grave, considering that legibility was a fundamental concern when he designed Futura, widly known as the first mass produced geometric sans-serif typeface.
Ah well, destroy your heroes and all that.