useful information

Glossary - D

Dagger and double dagger

Symbols used mainly as reference marks for footnotes.

Dampening

The necessary process in offset lithography of wetting the printing plate to prevent ink from adhering in the non-image areas.

Dandy Roll

A wire mesh cylinder used to smooth the top of paper as it forms. Enhancing surface smoothness and formation, the dandy roll may also carry a design, which will create a water- mark, identifying the sheet.

Dash

A short horizontal rule used for punctuation, either as an em or an en dash.

DCS

Acronym for Desktop Colour Separation. Originally introduced by Quark, it splits an image into five separate files: a low-res preview plus the four process channels, CMYK. Uses - bureaus can supply a designer with the low-res image only, at about 10% the total file size, these files are imported as FPO (For Position Only) into the layout. The FPOs are linked with the high-res files immediately prior to output. The low-res is useful too as it reduces the laser proofing time during the design process dramatically. There are two Photoshop DCS formats: DCS 1.0 and DCS 2.0 - DCS 2.0 supports a fifth, spot colour, channel.

De-bossed

An indent or cut in design or lettering of a surface.

De-bossing

Pressing letters or illustrations into a sheet of paper using a metal or plastic die to create a depressed (debossed) image.

Deckle edge

The feathery edge on a sheet of paper, created as the paper machine sprays a stream of water or a jet of air across the paper as it's being formed. Deckle edges can also be created after the paper is made, using a die. This method creates a less feathery, harder-edged deckle.

Deep etching

In 'old' technology the removal of unwanted material by routing away unwanted half-tone dots, now generally refers to applying a clipping path that masks unwanted areas. Digitally, the end is the same, the means a little different.

De-inking

removing ink and other finishing materials, like coatings, sizings, and adhesives from printed-paper. The complex de-inking process is what makes recycling paper difficult and ultimately adds to the cost of a recycled sheet of paper. To produce high-quality recycled or recycled content papers for printing and writing, the de-inking process needs to be thorough. The goal is to end up with reusable fiber that has few impurities, since impurities lower the quality of a recycled sheet and can some- times damage equipment in the papermaking and printing process. Modern offset and flexographic ink, photocopier and laser printing "ink," ultraviolet and thermography coatings, and adhesives make it increasingly difficult to de-ink paper. De-inking process see also bleaching, flotation, pulping wood, recycled paper.

De-lamination

The separation of a material into layers in a direction approximately parallel to the surface. The partial or complete separation of the layers of a laminate.

Densitometer

A photomechanical tool used to measure density of colour density in a transparency or in printed colour.

Density

The weight of a sheet of paper as compared to its bulk. For example, a paper that weighs more than another paper but is thinner has a higher density. Compacting the fibers creates a dense paper. See also bulk, weight.

Descender

Any part of a lower case letter that extends below the x-height, as in the case of g, p, q y and j.

Desensitizer Chemicals

Used in plate making making non-image areas of the plate unresponsive to ink.

Desktop Publishing

A process for creating camera ready and plate ready artwork on a personal computer.

De-staticisation

Treating plastic materials to minimize their accumulation of static electricity.

Diamond Engraving

A method of engraving metals using a non-rotating diamond tipped tool called a "diamond graver." As downward spindle pressure is applied, the point of the graver penetrates the surface of the material and scribes a fine line as the character is formed. This type of engraving is sometimes referred to as "diamond drag" or "scratch" engraving.

Diazo

Direct positive proofs made by contact exposure to film positives, can be made on paper or film.

Didot point

One Didot point = 0.0148 in, one English point = 0.013837 in.

Die

Any of various tools or devices used for imparting or cutting a desired shape, form or finish to or from a material. A device in converting machinery used for cutting only the face material of a pressure sensitive laminate or for punching out shapes from the entire laminate or any other material.

Die Cut

The line of severance between a pressure-sensitive label and its matrix or adjoining label made by the cutting edge of a die.

Die Cut Label

Pressure-sensitive labels mounted on a release liner from which the matrix has been removed.

Die cutting

Using a formed, meta-edged die to precision cut, or to cut shapes into a piece of paper. If a printing project requires a custom-made die, the total cost of the job will increase. See Laser Engraving.

Die life

Mileage expected from a new die and that expected following a re-sharpening of a die.

Die lines

A hand drawn or computer-generated layout of the die cut shape or shapes on a clear or matte finish acetate or mylar.

Die Stain

Used to check die cutting accuracy. Usually done with diluted ink applied to the die cut surface of the backing or liner material. The ink wicks into any fractures of the silicone coated surface, thereby exhibiting the problem areas.

Digital Imaging

The process of creating a digital output of an illustration, photographic image, computer file or other computer-generated materials. Output media can be film, paper, transparencies, vinyl and other materials.

Digital Photography

The process of recording images using a digital camera or a conventional camera with a digital adapter, it records on a disk or on microchip which can then be downloaded directly to a computer in tiff, pict or eps format.

Digital Printing

A type of printing which uses digital imaging process that transfers the image directly onto plain paper immediately, without traditional offset rollers and plates.

Digital signature

ensures that a message was actually sent by the person claiming to send it.

Dimensional Stability

A measure of paper's tendency to stretch or shrink, especially when affected by changes in moisture content from humidity, the printing process, or even the passage of time. Paper that maintains its original dimensions has a high degree of dimensional stability. See also grain, relative humidity, resilience, and runnability.

Dingbat

Ornaments used to embellish printed text.

Discrete code

A bar code or symbol in which the spaces between characters (inter-character gap) are not part of the code.

Dispenser

A device that deeds pressure sensitive labels, either manually or automatically, making them ready for application. It can serve as a package for the labels as well (dispenser boxes).

Dispensing edge

A relatively sharp edge around which a backing material is pulled in order to dispense a pressure sensitive label from that backing. Sometimes referred to as a peeler plate.

Dispersion

See de-inking

Display type

Larger type used for headings etc. Normally about 18 point or larger.

Dithering

Utilised when images are reduced from 24-bit to 8-bit colour. The dithering algorithm combines pixels of adjacent colours into a dot pattern, simulating unavailable colours. It reduces the posterisation effect that colour depth reduction can create. Photoshop offers two dithering options - the best is Diffusion Dithering (see stochastic screening).

Domain name

The unique name refers to an electronic web address, registered to the owner.

DOS

Disk Operating System (DOS in Windows environment, MacOS in Apple Macintosh environment and Linux et al): Software for computer systems with disk drives that supervises and controls the running of programs. The operating system is 'booted' into the computer from disk by a small program that permanently resides in the memory.

Dot

The smallest element of a halftone.

Dot area

Pattern of a halftone that consists of the dots and the spaces in between.

Dot Compensation

Adjusting the size of the dots in halftones or four-colour images to allow for dot gain and to ensure that the colour and detail of the image print as intended. See also dot gain, four-colour process, halftone, ink holdout, screen.

Dot gain

A printing term that describes wet ink coming in contact with paper and spreading, as it is transfers. As the halftone dots are applied to the paper, the wet ink spreads, causing the dots to increase in size and halftones to appear darker. Paper weight, type of paper (coated or uncoated), press type (especially web presses), affects the amount of dot gain in a given printed piece. You may compensate for dot gain by calculating the dot gain before a print job and lessen the density of the images to be printed before you output film. See also dot compensation, four-color process, and halftone.

Dot loss

When the image on the printing plate is less, or sharper, than that shown on the proofs. (The opposite of dot gain.)

Dot matrix printer

A printer in which each character is formed from a matrix of dots. They are normally impact systems, ie a wire is fired at a ribbon in order to leave an inked dot on the page, but thermal and electro-erosion systems are also used.

Dot-for-dot reproduction

The method of producing printing film by photographing previously screened image - a maximum 10 percent enlargement or reduction can be achieved.

Double burning

Combining multiple film images onto a single film to create a single image.

Double coated

A pressure sensitive product consisting of a carrier material with similar or dissimilar adhesives applied to the two surfaces and wound with a silicone release paper.

Double density

A method of recording on floppy disks using a modified frequency modulation process that allows more data to be stored on a disk.

Double digest fold

One of four basic folds in web printing that forms a sheet into a signature.

Double page spread

Two facing pages of newspaper or magazine where the textual material on the left hand side continues across to the right hand side. Abbreviated to DPS.

Double-dot duotone

When two halftone negatives -a shadow halftone and a highlight halftone - are combined onto a single plate. An image printed from this plate carries a much wider tonal range than a normal halftone.

Double-dot halftone

The combination of two halftone negs made from one con-tone image using different screen angles for each neg combined to make one printing plate.

Doubling

An offset printing defect - refers to a second set of dots causing a colour shift in the reproduction.

Doughnut

See Hickey.

Down time

Loss of chargeable time due to machine breakdown or other factors.

Downloadable fonts

Typefaces that can be stored on a disk and then downloaded to the printer when required for printing. These are, by definition, bit-mapped fonts and, therefore, fixed in size and style.

DPI (dot per inch)

The number of dots that fit horizontally and vertically into a one- inch measure. Generally, the more dots per inch, the more detail is captured, and the sharper the resulting image. See also halftone, lines per inch, screen.

Drawdown

The smear of ink produced by a smooth blade on paper. Used to check quality and tone of the colour on the paper stock to be printed on. Also checks chemical reaction of ink to paper.

Drawn on

Binding a paper cover to a book by drawing the cover on and gluing to the back of the book.

Dreamweaver

A WYSIWYG web page editor from Macromedia. Competitor with GoLive, from Adobe.

Driers

Usually metallic salts that speed ink drying.

Drop cap

An initial letter covering two or three lines of text type. Can be decorative.

Drop cap

A large initial letter at the start of the text that drops into the line or lines of text below.

Drop folio

Page numbers at the foot of a page.

Dropout halftone

Halftone with no dots in the highlight areas.

Dry End

The drying section of the papermaking machine, after the press section, at which point most water has been removed from the paper. As paper moves through the dry end, the drying process is completed and the paper reel is wound.

Dry litho

Offset litho plate that does not need dampening to keep the ink to its image area.

Dry transfer (lettering)

Characters, drawings, etc, that can be transferred to the artwork by rubbing them off the back of the transfer sheet. Best known is Letraset. Superseded by and large by graphics packages on computers

Dry Trap

A layer of wet ink being applied over a previous layer of dry ink in a separate run of the printing press. Dry trapping usually produces sharper images than wet trapping because prior wet or damp layers don’t dilute subsequent layers of ink. Dry trap- ping is also more expensive because the paper travels through the press more than once.

Drying

The step in the papermaking process that brings the moisture content of paper to approximately 5%. Moving the web of paper around a series of heated iron drums in the dry end of the paper machine does this. see also dry end, papermaking.

Dryography

Waterless offset lithography. This printing process is able to use extremely fine line screens to produce high-resolution printing.

Duct

The ink reservoir on a press.

Dull Coated

A coated paper finish that falls between glossy and matte.

Dummy

A complete layout, often run out as a Colour Laser Copy (CLC), with all pictures, illustrations and text in place, to size. This is used primarily to sell the concept to the client. Also known as a layout or a mock-up.

Dummy Text

See Placeholder Text.

Duotone

A two-colour halftone of the same images created with two screens, two plates, and two colours. Most halftones are one-colour halftones, printed with black ink on white paper. By blending the black of the tiny ink dots and the white of the paper, the human eye sees shades of grey. Printing an image with two colours, generally black and a second color makes Duotones. The full range of tones are printed black and the middle range of tones are printed in the second colour. The result is a striking image with more richness and depth that a one-colour halftone. Printing a tritone or a quadratone can further enhance the image; these are also reproductions of black and white images, perhaps with a touch of colour. The cost of printing tritones or quadratones may be as high as or higher than four-colour process printing.

Dust

Dust tiny, free pieces of fiber, filler, and/or coating on paper. During printing, dust may adhere to the blanket and create imperfections by not allowing ink to reach the paper surface.

DVD

Digital video disc, holds 4.7Gb as opposed to the 650Mb of a CD

DXF

AutoCAD format for line art.

Dye sublimination transfer

A photographic colour print using special coated papers to produce a full colour image. Can serve as an inexpensive proof.

DYE TEST

See die stain.