Treshold
Treshold is when you make an image only black and white!
Step 1: First you have to find an image you want to use. I'll be using this one:
Step 2: Click
Image >> Adjustments >> Threshold. A new window will appear, here you can choose the intensity of the treshold. I put my level at 128.
Step 3: When you are happy with how it looks click
ok and you're done. Here's my result: