Using just Photoshop, we're going to turn an ordinary photograph into a stencil worthy image in just a few minutes!

I was bored today and decided I wanted to make a stencil. Looking through my old profile pictures on facebook, I found a particular one that I thought might make a good stencil. After playing around for a bit, I discovered this process for turning it into a two-color image on photoshop.

Keep in mind, you can also use this for silk screening, or any other process that requires a smooth edged image.

Step 1: Rough Shapes

First we make it into a rough two-tone shape:

Load the image
Image>Adjustments>Posterize - You don't want it to look too different. I posterized it to 10 levels.
Image>Adjustments>Threshold - Slide the bar around until you see something that looks like a stencil. You have to keep it as simple as possible, for ease of cutting it out, and also watch out for islands that wouldn't be connected to the main stencil i.e. floating blobs. I set my threshold level to 100.

Step 2: Cleaning It Up

Right now we have a very rough, jagged stencil. It won't work well for cutting out with a knife at all. This step is what took me some time to figure out.

Filter>Blur>Gaussian Blur - Set the radius to a level that still leaves a distict image, but with evenly blurred edges. 4 pixels was perfect for me.
Posterize it again, this time at 2 levels, and you should be all set!

Step 3: What to Do With It?

I printed my stencil out, and then used a cardboard cutter to cut the stencil out from a shoe box. So far i've only spray painted it onto newspaper, but it definitely turned out well!

A few tips:

When you print it out, change the color from black to a light gray. It'll save you some ink.
This instructable gives some help on making stencils with islands.
A light layer of spray on adhesive can help give you cleaner edges when you're spray painting. Make sure to remove the stencil immediately after painting, or it may get stuck!

Have fun with your new stencil!

UPDATE: I ended up putting it onto a T-Shirt. Acetate sheets (over head transparencies) work well for reusable stencils, so I printed it onto one of them and cut the images out with scissors, and voila! It's drying as I speak.