Converting a portrait to black and white

I work at a plastic design shop and one of our gurs is leaving, so as a gag gift for the boss we are going to print his face on some 2 tone plastic. I need to convert the color picture to a black and white picture. The machine will only recognize black and white since it is only 2-tone plastic (no gray tones). Also the detail is limited as the cutting is done by a 1/16th inch bit. I am wanting to convert the picture below to a black and white only with enough detail to still recognize the person, but not so much detail so the CNC machine can easily cut the picture into the plastic. I have included an example of one that I printed for mothers day so you can see the kind of detail I'm looking for (it was a 10x15 inch piece). If anyone has any suggestions about how to get the best results or if you want to play around with the portrait, please feel free. thanks!

Portrait I need to convert:
LINK TO FULL SIZE IMAGE

If you turn it to a greyscale, up the contrast and than use the cutout feature you'll get a two tone image like what you're looking for. For a slightly more detailed look, if you have illustrator you can bring the black and white into that and do a live trace.

HOSTED PHOTO
please log in to view hosted photos in full size.

isophotostudio wrote in post #10295483
If you turn it to a greyscale, up the contrast and than use the cutout feature you'll get a two tone image like what you're looking for. For a slightly more detailed look, if you have illustrator you can bring the black and white into that and do a live trace.

Excellent. This is just what I was looking for. Thanks a bunch!