The translation of a computer file into a format that uses less disk space. Compressed files must be decompressed to be used. (See also lossless compression and lossy compression.)
Densitometer:
In printing a reflection densitometer is used to measure and control the density of color inks on the substrate.
Density:
A measure of the degree of blackness.
Density:
1) The degree of darkness of a photographic image. The darker a tone, the higher its density. 2) The thickness of a layer of printed ink. 3) The ability of a color to absorb light reflected from it or block light passing through it. 4) The tightness or looseness of paper fibers.
Desktop publishing (DTP):
The process of creating fully composed pages using a computer, off-the-shelf software, and an output device such as a laser printer.
Die:
A device for cutting, scoring, stamping, embossing or debossing.
Die cutting:
The process of using sharp steel dies to cut special shapes from printed sheets either on flatbed or rotary presses.
Disk drive:
Various internal or external devices that "read" information from and "write" information to computer disks of various types, such as SYQuest, Optical, and Bernoulli.
Dithering:
A technique for altering the values of adjacent dots or pixels to create the effect of intermediate values. Dithering refers to the technique of making different colors of adjacent dots or pixels give the illusion of a third color; for example, a printed field of alternating cyan and yellow dots appears to be green. Dithering can give the effect of shades of gray on a black-and white-display or the effect of more colors on a color display.
Dot:
1) Variable-sized spots found on film to which create the illusion of multiple colors or shades from one single color. 2) The individual element of a halftone.
Dot area:
The dot area is indicated by a percentage from zero to one hundred percent.
Dot gain:
An inherent characteristic of the printing process in which dots are enlarged, resulting in darker or stronger colors. Hi bulk paper has dot gain because it absorbs ink. Dot gain can be compensated for during film preparation or by using coated stock and heatset printing because the ink dries before it soaks into the paper.
Dots per inch (dpi)::
The unit of measure for output resolution, the dpi refers to the number of dots that will fit in an inch. DPI is also used to measure the quality of input when using a scanner. The DPI in this case, becomes a square function measuring the dots both vertically as well as horizontally. Consequently, when an image is scanned in at 300 dpi, there are 90,000 dots or bits of electronic data (300 x 300) in every square inch.
Double burn:
Utilizing two or more negatives to expose an image on a plate or positive print.
Drilling:
Punching holes in folded sections, trimmed or untrimmed, or in finished books, which will permit their insertion over rings or posts in a binder.
Dummy layout:
A mock-up of a job showing the placement of specific items or pages, and showing specific bindery characteristics.
Duotone:
Color reproduction from a monochrome original, such as a black and white photograph. Two halftones with different screen angles are made from the same original and printed in two colors. A duotone is printed in two colors but both plates can be used for the same color ink for maximum contrast. When using black ink this is called a "double black".
Electronic pre-press (EP):
Computers designated to work on customer created electronic files.
Electronic publishing:
A generic term for the distribution of information that is stored, transmitted and reproduced electronically.
Elliptical dot:
In halftone photography, elongated dots that give improved gradation of tones, particularly middletones; also called Chain Dot.
Emboss/embossing:
To press an image into paper so it is raised above the surface.
Enamel:
A type of coated paper or the coating material on a paper.
EPS (encapsulated PostScript):
A standard graphics format consisting of a PostScript code that tells the printer how to print the image and a PICT image that tells the screen how to display it.
Erasable/rewritable optical disk :
Optical disks that can be rewritten a large number of times at the user's workstation.
Exact reprint:
All negatives of a previous job are used again with no charge.
Face trim:
Area that is trimmed off the front (open) edge of the piece during the binding process.
Facing pages:
Two pages that face each other when a publication is open.
Fifth color:
A nonprocess or premixed ink color used in addition to the four-color process.
File format:
A set of instructions that describe how to store, access, or transmit digital information. Some examples are EPS, TIFF, PICT, DCS, JPEG. For graphics, use EPS and TIFF.
FIM (Facing Identification Mark):
Any one of four patterns of vertical lines on the address side of a reply card used to classify and sort types of mail.
Final trim size:
The finished size of a bound magazine.
Finishing:
Any post-press operation, such as folding, binding, etc.
Fit:
The alignment of two or more printed images on the same paper, negative, or other material. See register/registration.
Flatbed scanner:
A device that works similar to a photocopy machine. Used to import graphics and images into a variety of software programs.
Flush:
Aligned vertically on the left or right side of a page (flush left or flush right).
Fold marks:
Markings that show where folds should be.
Folding sample:
A proof or mock up that shows how an item folds.
Folio:
The page number.
Font:
A complete set of characters and symbols in one typographic design. To output to film both the Printer Font and its companion Screen Font are necessary.
Foot:
The bottom of a card, page or book.
Foot trim:
Area that is trimmed off at the bottom of the piece during the binding process.
Form:
1) The assembly of pages on a printed sheet. When folded, the form is called a signature. 2) A precise card layout which allows cards to be printed and collated in a designated order.
Four-color process:
Use of cyan, magenta, yellow, and black to create a full color image.
FPO (For Position Only):
Refers to inexpensive copies of photos or art used on mechanicals to indicate placement and scaling, but not intended for reproduction.
Gamma:
1) A measure of contrast in photographic images. Film types are listed as creating certain gamma ranges appropriate to different uses. 2) In electronic color correction, the difference in the status of the color curves. The color curve represents highlight to shadow values between current values and corrected values. Changing the color curve (making a gamma correction) increases or decreases the highlights, midtones, and shadows relative to the original points on the curve.
Ganged (to gang):
The grouping of two or more versions on a press sheet for greater efficiency.
Gate fold:
An insert where one or two pages are bound into a publication so that one or more pages will fold out from the publication.
Ghosting:
Phenomenon of a faint image on a printed sheet where it was not intended to appear.
Gigabyte:
An electronic unit of measure equal to about 1,000 megabytes of data (or 1,000,000 bytes). Abbreviated gb.
Gloss:
A shiny coating on paper. Gloss coatings allow very little ink absorption, thus providing excellent color definition and contrast.
Gradation:
Variation in tonal values, from white to black.
Grain:
1) In photography, the speckled appearance in prints or transparencies produced by clusters of silver particles in photographic emulsions. Frequently considered undesirable and apparent when an original is enlarged too much, grain can also be emphasized for special softening effects. 2) In paper making, the direction in which most wood pulp fibers lie within the sheet due to the direction of flow as the paper is made. Folding paper against the grain breaks more wood pulp fibers than folding with the grain, resulting in an uneven, less precise fold.
Gray component replacement (GCR):
Also called achromatic color replacement (ACR), integrated color removal (ICR), and polychromatic color removal (PCR). Removing the achromatic (also called contaminant or graying) component of cyan, magenta, and yellow when they all combine and replacing it with black. Gray component replacement is distinct from under color removal, which reduces process colors in only dark, neutral areas and adds black. GCR separation is done with specialized software on electronic scanners.
Grayscale:
A black and white image with shades of gray such as a halftone.
Grid pattern:
The shape of halftone screen dots. Some common shapes are linear, elliptical, and round. Different shapes cause different effects in the final output.
Gripper edge:
The leading edge of a sheet which is held by the grippers.
Gripper margin:
The unprintable area of the paper where it is gripped as it passes through the press.
Gutter:
The inside margin from the printing edge to the binding area for publications.