<p>Improved posterboard (10) is formed from a rectangular posterboard (10) having vertical side edges (12, 14) and horizontal top (16) and bottom edges (18). Guide marking (20) are applied to the posterboard (10). The guide markings (20) are visually perceptible at a writing distance away from the posterboard (10), and substantially imperceptible at a viewing distance length away from the posterboard (10).</p>
