Offset printing puts wet ink on paper, which is then allowed to dry before cutting and finishing. But even totally “dry” ink can rub off, given enough friction. This problem is called “offsetting”, and it can create smudges on other print projects.
Offsetting is more likely to occur when:
- There are larger areas of “heavy” coverage (i.e., lots of ink on the paper)
- Printed pieces are packed together tightly (the weight of the pieces causes friction, which makes the offsetting occur)
- Weight is put on printed pieces
- Printed pieces are being mailed
You can do a simply demonstration to see offsetting yourself: take a printed piece with a large area of ink (blue or green show up best). Then rub the piece vigorously, with pressure, on a piece of white paper. Unless the printed piece was coated, a small amount of ink will smudge on the white paper.
Although offsetting is most noticeable with dark, vibrant colors (think rich blues and greens), it can happen with any color ink.
There are several things you can do to avoid offsetting:
- Allow ink time to dry—appropriate drying might add an additional day to your turn-around time.
- If your printed piece has large areas of color (which require a lot of ink), consider getting an aqueous coating or varnish on your piece. This costs a little more, but preserving the quality of your piece is often worth it.
- If you are going to ship large quantities of printed pieces, ask to have them “slip sheeted” (i.e., put blank scrap paper between pieces). This won’t prevent offsetting, but at least the ink will rub off on the scrap paper, instead of your pieces.
- Also consider having pieces shrink-wrapped for shipping.
- Avoid large areas of white on the front and backs of printed pieces (light colors make offsetting more noticeable).
- Get extras! If a few pieces are ruined by offsetting, it is a good idea to have back-ups.
Remember, offsetting can occur on any offset piece, regardless of how much time the piece has had to dry. A coating is the best way to prevent this problem.