1. Open up your image.
2. Change the name of the layer from
Background to PHOTO. It will help you keep track of your layers....all two of them.
3. Next, change the levels of the picture (Image > Adjustments > Levels).

The levels I always work from are 60, 0, 220, and you adjust from there. The first number affects how dark the black parts of the image are, and the last number affects how bright the light parts are. You want the dark parts to be fairly dark and the light parts to be fairly bright. Here, I've changed the levels to 30, 0, 150. Just do whatever looks best to you.

See the difference?
4. Next you're going to add the Film Grain effect (Filter > Artistic > Film Grain).

Set the Grain to 4, Highlight Area to 0, and the Intensity to 10.
5. Duplicate the layer and label it HALFTONE.
6. Now we're going to pixelate the image by going to Filter > Pixelate > Color Halftone.

Choose whatever number looks best to you for the Max Radius (the bigger the number, the bigger the dots). The input has to be at least 4. With smaller pictures, 4 works best, but the bigger the picture, the bigger the number you'll want....unless you're zooming in really far.
7. Finally, set the blending mode of the HALFTONE layer to "darken," and you've got your comic book effect!

You can go back and change the size of the dots if you want.