The term originates from moire (moiré in its French adjectival form), a type of textile, traditionally of silk but now also of cotton or synthetic fiber, with a rippled or “watered” appearance.
Sometimes, some photographs also develop the moiré effect (like a criss-cross pattern) when they are printed.
There are many factors that cause the moiré effect on a printout.
Two of them are the most common. (Meaning, of course, factors related to the graphic artist’s job and not the printer’s responsibility or the dot-matrix format used.)
- Bad scanning from the original printout.
- Excessive contraction of a photograph on a page make-up program.
We can prevent the development of the moiré effect by following two simple steps:
- We should scan pictures from printed files using a special filter existent in every scanner. It’s usually the descreening option.
- Moiré usually appears on digital photographs when the pictures include patterns like plaid. In these cases, we should reduce the photographs to the size we want them to be printed using Photoshop, before we insert them in the page make-up program.
Tip: Before we hand in any project to be printed, we should print a natural-sized sample on our own printer. Those kinds of mistakes are easy to spot on a sample (provided we use a high resolution printer). If we have doubts about a photograph, we can always ask for a hard proof, just to make sure).