The technical definition: a halftone is a matrix of different size dots which allow printers to simulate tonal variation when printing with a single ink on press. What this means: a halftone allows you, using one color ink, to approximate various shades of color. Take a magnifying glass and look at a black and white photo printed in your local newspaper. You’ll notice the image is actually made up of different size dots. The smaller the dot, the lighter the color in the halftone. A grayscale is made up of pixels that are in varying shades of black so the tones are represented by the different shades. Once a file has a line screen applied, the grayscale is now a halftone.