Adding halftones is a pretty neat effect – and it’s very easy to do using Adobe Photoshop. Halftones mimic the old school method of offset printing used in pulp comic books. You can add them by going to the Filter > Color Halftone menu.
What I like to do before adding halftones is to first flatten the colors to a single layer, then duplicate the layer (Command-J on Mac, Control-J on Windows). It’s on the upper color layer where I apply the halftone effect. Finally, I reduce the opacity of the ‘half-toned’ layer to minimize the effect.
Here’s what my layers look like:
The Color Halftone setting operates on two parameters: the Maximum Radius (size of the half-tone dots) and the 4 Channel settings. Each channel setting corresponds to Cyan, Magenta, Yellow and Black, respectively. The Max. Radius value has a minimum value of 4. You’ll want to adjust the size according to the size of your file and the effect you want to achieve.
You can also fiddle around with the values for the 4 channels to see how you can affect the halftone’s color – or keep them all the same numerical value to insure that the halftones are displayed as one unified color.
The halftone effect works great for gray scale and color illustrations. Give it a try!