A paper coloring apparatus particularly for rotation printing presses and, ordinarily for the coloring of white paper to the desired color before the paper web (2) is drawn into the printing press. The paper web (2) passes over several guide rollers (3, 4, 5) plus a displaceable roller (8) which can be displaced towards and away from a coloring roller (10). The coloring roller (10) is supplied with dye from a dye bath (12) via a dye roller (13) which communicates with dye bath (12), and a displaceable intermediate roller (14) which can be displaced towards and away from engagement with the dye roller (13) and coloring roller (10). The displaceable rollers (8, 14) are displaced with the aid of compressed air cylinders (11, 15), and the pressure of the displaceable rollers (8, 14) against the counter-rotating rollers (10, 13) is regulated with the aid of regulation valves in the appropriate compressed air circuits. The displaceable roller (14) has a moveable support such that it automatically adjusts to constant alignment in both horizontal and vertical planes with uniform pressure along the entire length of the displacement roller. The paper coloring apparatus according to the invention may be arranged alternatively to color the top and bottom sides of the paper web (2).