Offset Printing -
Printing technique that transfers ink from a plate to a blanket to
paper instead of directly from plate to paper.
Opacity - (1) Characteristic of paper or other
substrate that prevents printing on one side from showing through
the other side. (2) Characteristic of ink that prevents the substrate
from showing through.
Onion Skin - A specific lightweight type (kind)
of paper usually used in the past for air mail. Seldom used today
(in the typewriter era).
Opaque - (1) Not transparent. (2) To cover flaws
in negative with tape or opaquing paint. Also called block out and
Open Prepress Interface - Hardware and software
that link desktop publishing systems with color electronic prepress
Outer form - Form (side of a press sheet) containing
images for the first and last pages of the folded signature (its
outside pages) as compared to inner form.
Outline Halftone - Halftone in which background
has been removed or replaced to isolate or silhouette the main image.
Also called knockout halftone and silhouette halftone.
Overlay - Layer of material taped to a mechanical,
photo or proof. Acetate overlays are used to separate colors by having
some type or art on them instead of on the mounting board. Tissue
overlays are used to carry instructions about the underlying copy
and to protect the base art.
Overlay Proof - Color proof consisting of polyester
sheets laid on top of each other with their image in register, as
compared to integral proof. Each sheet represents the image to be
printed in one color. Also called celluloid proof and layered proof.
Overprint - To print one image over a previously
printed image, such as printing type over a screen tint. Also called
Over Run - Additional printed matter beyond order.
Overage policy varies in the printing industry. Advance questions
avoid blind knowledge.