Customized version of http://www.thingiverse.com/thing:1216198

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=1216198

Using the following options:

inner_radius = 45
white_threshold = 1
outer_radius = 50
black_threshold = 0.01
build_plate_selector = 0
black_min = 0.05
white_max = 0.95
cutoff = 70
build_plate_manual_y = 100
build_plate_manual_x = 100