In digital halftone technology, dot reproducibility is an important factor because our perception and recognition of an image depend on the characteristics of the printed dot. Halftone dot size variations reproduced by typical printing technologies, such as electrophotography, offset, and flexography, were investigated to determine their dot reproducibility. The investigation found that offset, flexography, and electrophotography can produce halftone dot sizes with a percentage coefficient of variation (%CV) at 8.88, 19.64, and 13.93 consecutively in the highlight image areas (small dot size), while the %CV of halftone dot size variations tend to decrease when the dot size increases in the midtone and shadow image areas. The perception of simulated halftone dot size variations was then studied experimentally under set observation distance and halftone frequency conditions in order to analyze the relation between human perception and halftone dot size variations. It was determined that human perception detects nonuniform halftone image dot patterns when the %CV of the halftone dot size variation is greater than 6.72.