1. A process for printing printing substrates, the process comprising the following steps: assigning pixels of a multilevel map to image dots of a printer-ready copy and assigning values to the pixels depending on a tonal value of the image dot, permitting n+1 different values to be assigned to each pixel, where n is greater than 1; representing different amounts of ink of a printed pixel with the different values; assigning threshold values of any threshold value matrix to the pixels of the multilevel map with respect to their positions relative to the printing substrate; sorting the threshold values of the threshold value matrix in increasing or decreasing order; assigning each threshold value an XY value for an imaging of the printing substrate; representing an assignment of the values to the threshold values in the form of a 2D graph; forming an abscissa of the 2D graph by the threshold value itself and forming an ordinate of the 2D graph by the value of the pixel of the multilevel map, with at least one curve being plotted on the graph and it being possible for the at least one curve to correspond, in particular, to a tonal value to be printed; and assigning to each threshold value a value of the pixels in the multilevel map resulting from the position of the threshold value on the abscissa axis and the value on the ordinate axis assigned by the at least one curve; calculating tonal values of the image dot with color separation; fixing the values of the pixels depending on the threshold value and on the tonal value of the assigned image dot; and printing the multilevel map on a printing substrate in a multilevel printing process.