This effect was generated in Filter Forge, a Photoshop plugin that allows you to create your own filters.
A digital halftone CMYK image.
In a true halftone image the four printing colors are at different angles. In this digital halftone, the likes of which you may find in a digital press or some color laser printers, they are all at the same angle.
"Original softness" blurs the source image before generating halftone dots.
"Dot gain" simply makes the image darker by the given percentage.
For best results, adjust Registration to offset dots so that they don't print directly on top of each other. Alignment is "perfect" at setting 50, which means dots print exactly on top of each other, which is not usually desirable.
halftone, dot, pattern, CMYK, separations, screen angle, gain, digital press, color laser printer