Ghost effect
A ghost effect or ghost is a contact effect or printing error that can occur in offset printing, among other things . This creates an undesirable weak imprint of what was previously printed. There are two types of ghost effects:
Mechanical spirits, also called stenciling ( stenciling ), are characterized by the appearance of a “phantom” image on a printed page. They occur during printing and are immediately visible. They are caused, for example, by insufficient ink, since the inking roller does not always apply enough ink to the plate after printing areas that are heavily saturated with ink.
Chemical ghosts, also known as the gloss-matt effect , arise when paper is printed in stacks and on both sides. They appear as a "phantom" image on the back of a printed sheet (reverse printing ), which is caused by the front side of the sheet ( the face printing ) of the sheet below in the stack. It is probably caused by the reaction of gases from drying ink with the ink on the sheet above, changing its drying and thus often also the gloss. This can happen days after printing.