Fourth plight black is needed by a printer to make block or shopping and darken the image being produced. In commercial terms, these process colors are commonly referred to cm y k. The K refers to black, and means key color. This also avoids any confusion with black and blue. These four process links can be printed as solid or tinted layers with which all other colors can be achieved. A tinted layer is normally printed as a pattern of round dots. Printing can reproduce color photographs convincingly with the full process inks in halftone patterns that overlap at different angles.