Dot Dot Dot
I was recently asked how to create this cute little Zip-A-Tone dot effect using Photoshop. Here's a detailed guide. It's super easy!
A. You need to make sure the image mode is on Grayscale.
B. Throw some grays down (you can also take a photo and blow it up to create some interesting effects).
C. Go to Filters, Pixelate, Color Halftone.
D. Fiddle with the pixel radius to get the right size dots. It depends on the dpi you are using and how big you want the dots to be.
You can create similar effects in color, but when you do that it gives you CMYK dots, and I kind of feel like you have less control. When I've been working in color, I've created the dots in grayscale first, and then switched to RGB or CMYK.