Dampening System 

The mechanism on a press for transferring fountain solution to the plate.

Data Shift 

In process color printing, it describes a shift in one of the channels of data that comprise the image file and could cause inconsistent color in some areas in the image.

DDES 

Direct Digital Data Exchange Standards. A set of established formats, protocols and values allowing one vendor's equipment to exchange data with another vendor's equipment.

Deckel Edge 

The untrimmed feathery edges of paper formed where the pulp flows against the wire of a paper making machine.

Dedicated Device 

A piece of hardware that is permanently assigned to one task. The task, however, can be changed by reprogramming or by the introduction of different software.

Default 

Software setting that returns specifications to a relative "home base" in the absence of other instruction from the operator. Depending on the software, new default settings can be made for one or more functions.

Densitometer 

A quality control device to measure the density of printing ink.

Instrument used to measure density. Reflection densitometers measure light reflected from paper and other surfaces. Transmission densitometers measure light transmitted through film and other materials.

Density 

The amount an object absorbs or reflects light is called "density level." High-density objects absorb or stop light; low-density objects reflect or transmit light.

The degree of color or darkness of an image or photograph.

Descender 

The part of a lower case letter which extends below the main body, as in "p".

Desensitizer 

Chemical agent used to make non-image areas of a printing plate repellent to ink.

Desktop black and white scanners 

Used to make black and white negatives or positives of images or line art.

Desktop color scanners (CCD) 

Less-expensive, usually flatbed devices using charge-coupled devices (CCDs) to bring color prints or negatives into a computer for manipulation, separation or printing.

Desktop color scanners (PMT) 

Drum-type devices using photomultiplier tubes (PMTs) to bring color prints or negatives into a computer for manipulation, separation or printing.

Desktop Color Separation Files 

A set of Encapsulated PostScript files (EPS) that provides color separation information. The DCS set includes one master file and four separation files.

Desktop publishing stripping 

Electronic assembly of all elements in final imposition for direct output as composite negative or plate.

Desktop Publishing 

Using a personal computer to compose pages of type and graphics and output the finished work to a laser printer or imagesetter onto paper, film or printing plate.

Detail Enhancement 

The technique of exaggerating picture image edges with unsharp masking or peaking, so the observer can easily see the detail of the original in the final reproduction.

Device Driver 

A miniature program that acts like a translator, converting the output from one device into data that another device can understand.

Diazo 

A light sensitive coating used on printing plates.

Die cutting 

Curing images in or out of paper.

Die Stamping 

Printing from lettering or other designs engraved into copper or steel. Also called the intaglio process, it is used for the production of letterheads, business cards, etc.

Die 

Device for cutting, scoring, stamping, embossing or debossing.

Metal rule or imaged block used to cut or place an image on paper in the finishing process.

Diecutting 

Using sharp steel rules to cut special shapes from printed sheets. Diecutting can be done on either flatbed or rotary presses.

Digital graphic design services 

Staffing to provide desktop publishing design or page makeup services to customers.

Digital photography 

Direct electronic capture of an image within a camera without using film and processing.

Digital Plates 

High speed or spark discharge plates that can be exposed by digital data from a prepress system.

Digital Printing 

A new kind of printing process particularly good for short-run jobs that need fast turnaround times. Digital printing does not use film but digital imaging technology instead. It's still working its way into the mainstream.

Printing by plateless imaging systems that are imaged by digital data from prepress systems.

Digital Soft Proof 

A color video monitor display of a picture file, data file or text file.

Digital 

Information that relies solely on Arabic numerals for expression. In computers, all information is processed in binary numerics (0 and 1) through on/off electrical impulses. Computer programs are written in alphanumeric code (all keys on a keyboard) and are translated by programs or devices into binary code that can be read by the CPU of the computer.

Digitally stored photo libraries 

Storage of customers' electronic production files for possible future use (akin to storing customer negatives).

Dimensional Stability 

Ability of a film to hold size throughout its cycle of use. Polyester-based films are more dimensionally stable than acetate bases; glass is more stable than polyester.

Direct Digital Color Proof (DDCP) 

A proof made directly from the stored data file onto a substrate using a peripheral device such as a photographic exposure, dot matrix printer or ink jet printer without producing intermediate films.

Direct Screen 

The method of color separating which adds dots at the same time the transparency is being photographically separated into the four colors.

Direct-to-plate 

Often used as a synonym for computer-to-plate but less desirable to use because the acronym DTP can be confused with desktop publishing, which is also known as DTP (see computer-to-plate).

Dither 

To fill the gap between two pixels with another pixel having an average value of the two to minimize the difference or add detail to smooth the result.

Dot Area 

The size of the dot is indicated by the percentage of the area it occupies from zero to one hundred percent.

Dot Etching 

Applying chemicals by hand to either negatives for increasing dot size which adds color; or, to positives for decreasing dot size which subtracts color.

Dot gain or spread 

A term used to explain the difference in size between the dot on film v paper.

Dot Gain 

The increase in the printing dot size from the halftone film to the printed substrate resulting in darker tones.

Dot 

An element of halftones. Using a loupe you will see that printed pictures are made many dots.

The individual element of a halftone.

Dots per inch (dpi) 

The measurement of resolution for page printers, photo type setting machines and graphics screens. Graphics screens usually reproduce 60 to 72 dpi, most page printers 300 dpi, and typesetting systems 1,000 dpi.

Double Black Duotones 

Image created from two halftones, one for highlights and the other for midtones and shadows. Both plates are inked with black for the most contrast.

Double burn 

Exposing a plate to multiple images.

Utilizing two or more negatives to expose an image on a plate or positive print.

Draw-down 

A sample of ink and paper used to evaluate ink colors.

Sample of inks specified for a job applied to the substrate specified for a job.

Drier 

A substance added to ink to hasten drying.

Drop Out 

The technique that can give a mediocre photo greater contrast by photographically removing some dots to create highlights that show the actual white of the paper.

Portions of artwork that do not print.

Drum 

The common name for the photoconductive cylinders used on scanners and plotters.

Dummy 

A layout showing the size, shape, form and general style of a piece of printing.

A mock-up of a proposed publication design including all the pages fastened together, and often containing art and type taken from other printed materials.

A rough layout of a printed piece showing position and finished size.

Duotone 

A halftone picture made up of two printed colors.

Two films are made by changing the screen angle for each and one plate is made for each film. 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".

Duplex Paper 

Paper with a different color or finish on each side.

Dylux ® 

Photographic paper made by DuPont and used for bluelines.

DuPont's light-sensitive proof in blue orblack.

Electronic Data Interchange (EDI) 

Industry-standard computer database and communication systems for intra- or inter-company exchange of information such as inventories, orders and invoices.

Electronic Dot Generation 

Method of producing halftones electronically on scanners and prepress systems.

Electronic file storage 

Storage of customers' electronic production files for possible future use (akin to storing customer negatives).

Electronic Mail or E-Mail 

A message service that uses telecommunications and electronics to deliver soft or hard copy information.

Electronic prepress training for customers 

Either formal presentation classes or informal one-on-one telephone help to customers using new digital technologies.

Electronic printing, black or spot color 

Technology that reproduces pages in black or black plus spot (highlight) colors directly from a computer file without negatives, plates, etc., typically using electrostatic or electrophotographic processes.

Electronic printing, full color 

Technology that reproduces pages in process colors directly from a computer file without negatives, plates, etc., typically using electrostatic or electrophotographic processes.

Electronic Publishing 

A configuration of hardware and software used for digital page composition. The term includes desktop publishing and high-end systems.

Electrophotography 

Image transfer system used in copiers to produce images using electrostatic forces.

Electrostatic printing 

Similar to photocopying, electrostatic printing is good for very short printing runs.