Printing Terms

A

Aliasing (jaggies):

Visibly jagged steps along angled lines, or object edges due to sharp tonal contrast between pixels.

B

Bitmap:

A digitized image that is mapped into a grid of pixels. These types of images cannot be enlarged or printed at higher resolutions without developing jagged edges (aliasing/pixelization).

Bleed:

An extra amount of image that extends beyond the trim-edge of the page.

C

Camera Ready:

Reflective artwork that needs to be shot with a copy camera to transfer to negative film.

Choke & Spread (trapping):

The process of creating a slight overlap between adjacent colors (called a trap) in order to keep the paper color from showing through.

D

Defining Color:

The color, usually the darker color, whose shape defines the object. The defining color should not be choked or spread, as that would compromise the image.

Dot Gain:

When an ink dot enlarges through absorbtion on a porous paper. This affects the overall tone of an image, as the size of the dot is equivalent to the tone it represents.

Down-sampling:

The reduction in resolution of an image, resulting in a loss of detail.

Duotone:

A halftone that is printed as a two-color image by replicating a portion of the original tonal range for the second color. The halftone screens must be angled 30 degrees apart.

E

EPS:

Encapsulated PostScript. A standard file format that allows vector and bitmap graphics, as well as page layouts, to be placed into other documents. EPS files cannot be manipulated, and need to be trapped in the parent program.

F

Final Size:

The size of the printed piece after folding and any finishing work.

Flat Size:

The size of the printed piece before folding.

G

H

Halftone:

The reproduction of continuous-tone artwork (such as a photograph) through the application of a screen that converts the image into dots of various sizes. (See the resolution section in the Building Electronic File Module)

Highlight & Shadow Detail:

In a halftone, the image detail at either end of the tonal range that is difficult to hold when printing. Highlights often get "blown out" (lost) and the shadow detail often gets "plugged" (filled in). You can control this by preparing your halftones for the specific paper stock used. See the Inkworks Scanning specs for details on preparing your halftones appropriately.

I

Imagesetter:

A photographic device that interperets the postscript description of a page through its Raster Image Processor (RIP) to image the graphical data directly onto film.

Imposition:

The layout of pages in the position they will be printed on the press-sheet.

Interpolation:

The computer's way of increasing image resolution by filling in new pixels. The pixels' color or tonal range are based on neighboring pixels.

Imported Graphics:

Graphics and photos that are created in one program, such as Adobe Illustrator, and imported into another, such as QuarkXpress, for final output.

J

K

L

Line Art:

Art that is made up of continuous lines such as pen & ink drawings or typefaces. There is no tonal difference from one area to another.

Line Screen (lpi):

The number of lines or spots per inch on a halftone screen. (See the resolution section in the Building Electronic File Module.)

M

Moir?:

An undesirable pattern created when overlapping screen angles are incorrect. Screens should be at 30 degree angles to each other.

N

O

P

Posterization:

An effect that is achieved by converting an image with continuous tonal range (such as a photo) to one with a limited number of visible steps/bands.

Printer Font:

The part of a postscript font that defines the shape of the font for the postscript printer, e.g., an imagesetter or laser printer.

Printer Spreads:

When the pages are ordered as they will print, rather than how they will be read. This relationship is determined by the amount of pages in the document, and the sheet size they will be run on.

Process color:

Color created by the subtractive primaries, yellow, cyan, magenta and black inks in order to create the appearance of the a full-spectrum of colors. Often refered to as "four- color process".

Q

R

Reflective Art:

Artwork that must be photographed from light reflected from its surface. Generally used as camera ready art.

S

Screen Font:

The part of a postscript font that defines how to draw the font cleanly (not bitmapped) on the monitor.

Stripping:

The final positioning of film negative pages onto a goldenrod flat prior to plate making.

T

TIFF:

Tag Image File Format. An image file format that is supported by the majority of image-editing programs, running on a wide variety of computer platforms.

Tints:

Various even tone areas (strengths) of a solid color. Created by converting the area to a set dot size.

Tonal Curves:

These curves are used to adjust smoothly the tonal range of a scanned image. Curves can be adjusted for the overall image, a selected portion of the image, or individual color channels (CMYK). See the Scanning section for more information.

U

Unsharp Mask:

A filter in Adobe Photoshop used to make an image look crisper. The filter identifies where two tones adjoin and increases the contrast. The user can control the amount of contrast applied and the amount of pixels affected.