How do I handle dot patterns or moiré effects when scanning artwork from printed sources?

Dot patterns, known as moire effects, appear when you scan artwork that was originally produced with 4-color process printing. The halftone dots from the first print show up at high scan resolutions and can clash with the grid of a new print.

• Lower the DPI: scanning at a more moderate resolution reduces how strongly the halftone dots register.
• Change the angle: rotating the original slightly on the scanner bed can break up the interference pattern.
• Blur or reduce noise: apply a slight blur or a noise-reduction filter in Photoshop before you submit the file.
• Rebuild clean elements: recreate logos or text as vector art so no scanned dots remain.

When the pattern is stubborn, combining a lower scan resolution with light softening usually gives the cleanest result before printing.