- download both part and trace views
- change file types to png


edit trace:
- picture, mirror, horizontal
- picture,brightness/contrast, unlink sliders, red max bright, blue and green min bright, all max contrast
(turns traces light red)
- picture, simple brightness/contrast, min brightness max contrast, repeat once
(darker red)

edit parts:
- add alpha channel
- flood alpha channel with grey 128

open trace in preview and paste parts.  use photoshop to correct on parts if needed.  if you're very lucky, it won't be necessary
(parts is now aligned with traces)

duplicate parts to mask:

edit mask:
- remove alpha
- picture, simple brightness/contrast, -50 bright max contrast, repeat once
(all light grey missing parts should be gone)
- picture, color, grey scale, 256 greys
- picture, simple brightness/contrast, -50 bright, maxcontrast
- picture, simple brightness/contrast, min bright max contrast, repeat twice
(picture is entirely masked)
- flood fill any parts with black that are hollow white
- now the fun part.  blow up to 500% and flood fill the parts.  this takes an hour or so
- picture, simple brightness/contrast, max brightness

edit parts:
create alpha, and paste the mask in

Open traces in preview and paste mask

save overlay