Registration marks

Registration marks - Flash animation

The paper is prepared by first tearing each sheet to the same size and with right-angle corners. All the papers are then piled with their printing surface down and with their watermarks facing in the same direction. Pencil marks are lightly ruled on the reverse side of each sheet. These marks should be approximately 1 cm in length and in the center of each end, parallel to the vertical of the sheet. The line at the left end of the sheet is crossed vertically with a short line called the T-bar. This enables the printer to tell one end of the sheet from the other and ensures that each sheet will be identically placed on the printing surface.

The printing plate is prepared with register marks similar to those on the paper. These may either be scratched and etched in the. The left side of the stone at midpoint should carry a vertical line 1 cm long put in the place where the edge of the print paper will be laid. A horizontal line of the same length is butted to the vertical, forming a T the reverse of the T on the print paper. A similarly positioned horizontal is drawn on the right side of the stone starting where the right-hand edge of the print paper will lie. The paper is positioned by aligning the left edge of the sheet with the T-bar on the printing surface and by lining up the horizontal lines at both ends of the sheet and printing surface to form continuous lines.

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The accuracy of this excellent system of registration depends on several factors. Because the positioning of the sheet is controlled only by visual means, it is important that marks on the paper and printing surface be in exact alignment. All registration marks should be extremely fine and absolutely accurate in measurement and positioning on each sheet of paper and on each color plate. The printer should lean over the plate when positioning the paper to avoid distorted or foreshortened views of the alignment. Slight errors in the positioning can seldom be detected until the next color is printed. Another problem results from the irregularity of the deckle edges of handmade papers. These prevent a tight butting of the sheet against the T-bar on the printing surface. For absolute accuracy, the deckle for each sheet should be slightly trimmed with a razor blade to offer a 1 cm straightedge at this point. Properly executed, the deckle trim is imperceptible against the irregularity of the sheet edge.