A method of mounting and adjusting printing plates on plate cylinders (15, 25) of a multicolour offset printing press, the method comprising the following steps: a) clamping a leading end of a printing plate in a front clamping bar of the plate cylinder (15, 25); b) wrapping the printing plate around the circumference of the plate cylinder (15, 25); c) clamping a trailing end of the printing plate in a rear clamping bar of the plate cylinder (15, 25), which rear clamping bar is movable under the application of a tensioning force and occupies, upon clamping of the trailing end of the printing plate, a tension-release position (Figure 6a; Figure 7a); d) tensioning the printing plate by applying a nominal tensioning force (Fo) to the rear clamping bar, thereby causing the rear clamping bar to move from the tension-release position (Figure 6a; Figure 7a) to a nominal tensioning position (Figure 6b; Figure 7b); e) setting and storing the nominal tensioning position as a reference position (Figure 6c; Figure 7c) of the rear clamping bar; the method being characterized in comprising the following steps: f) once all printing plates have been clamped and tensioned on their corresponding plate cylinders measuring a print register of the tensioned printing plate (P*); g) comparing the measured print register of the tensioned printing plate (P*) with a target print register and determining a corrected tensioning position of the rear clamping bar corresponding to the target print register; h) releasing the tension of the printing plate (P, Figure 6d; Figure 7d); i) setting the previously-determined corrected tensioning position as new reference position of the rear clamping bar before (Figure 6d) or after (Figure 7e) tensioning again the printing plate; and j) if necessary, repeating steps f) to i) until the measured print register matches the target print register. a) clamping a leading end of a printing plate in a front clamping bar of the plate cylinder (15, 25); b) wrapping the printing plate around the circumference of the plate cylinder (15, 25); c) clamping a trailing end of the printing plate in a rear clamping bar of the plate cylinder (15, 25), which rear clamping bar is movable under the application of a tensioning force and occupies, upon clamping of the trailing end of the printing plate, a tension-release position (Figure 6a; Figure 7a); d) tensioning the printing plate by applying a nominal tensioning force (Fo) to the rear clamping bar, thereby causing the rear clamping bar to move from the tension-release position (Figure 6a; Figure 7a) to a nominal tensioning position (Figure 6b; Figure 7b); e) setting and storing the nominal tensioning position as a reference position (Figure 6c; Figure 7c) of the rear clamping bar; f) once all printing plates have been clamped and tensioned on their corresponding plate cylinders measuring a print register of the tensioned printing plate (P*); g) comparing the measured print register of the tensioned printing plate (P*) with a target print register and determining a corrected tensioning position of the rear clamping bar corresponding to the target print register; h) releasing the tension of the printing plate (P, Figure 6d; Figure 7d); i) setting the previously-determined corrected tensioning position as new reference position of the rear clamping bar before (Figure 6d) or after (Figure 7e) tensioning again the printing plate; and j) if necessary, repeating steps f) to i) until the measured print register matches the target print register.