The dot fidelity of ink jet dots has been investigated for several different coated ink jet papers. Serafano and Pekarovicova have defined dot fidelity in terms of dot area and roundness. For ink jet printers, we can also define a nominal dot area and an “ideal” dot area, once the resolution of the printer is known. The nominal dot area is the area of the square pixel defined by the inverse of the resolution of the printer. The “ideal” dot area is defined as the area of the circle in which the square pixel can be inscribed. This is the smallest circular dot that will cover 100% of the area when all dot positions are printed. This pixel area is π/2 times the area of the square pixel. Thus, we can compare the actual printed dot size with both nominal and ideal dot sizes. This analysis provides a direct interpretation of dot gain, which can be compared with values obtained from densitometry. The dot areas observed in our laboratory varied between 1.25 and 13 times the ideal dot area, depending on the resolution of the printer and whether the coating was matte or glossy.