A Beginner's Guide to Printing & Paper Terminology

aliasing

The ragged, stair-step edges on slanted or curved lines, or on boundaries between colors, in computer imagery. The effect can be lessened by choosing the “anti-aliasing” option while working in Adobe Photoshop.

basis size

The standard size for a given type of paper stock: 25 x 38 for book papers, 20 x 26 for cover papers, 221⁄2 x 281⁄2 for bristols, and 251⁄2 x 301⁄2 for index.

basis weight

The weight in pounds of a ream (500 sheets) of paper cut to a given standard size for that grade; e.g. 500 sheets of 50-lb. book paper (whose basis size is 25 x 38 inches) weigh fifty pounds.

bit map

Computer image made up of dots (pixels). Each dot represents one bit. Low resolution bit-mapped images may look fine on your computer screen, but look crude and “computerized” when printed.

bleed

Printing that extends to the edge of a sheet or page after trimming. To ensure ink coverage to the bleed edge, bleed materials should extend at least 1⁄8 inch beyond the trim size of the publication.

blueline

Photographic proof made from stripped negatives where all colors show as blue images on white paper. Bluelines are used to check positions of images and pages, as well as a point of final proofing for important typographic changes. Changes made to a publication at this point can be costly, so it always wise to use b&w laser proofs before you send your job to the printer.

camera-ready

Nowadays. most design projects are entirely digital. They’re sent to the printer on a computer disk, from which the printer can output film negatives to produce the plates needed to print the piece. However, sometimes a photograph or other hard-copy artwork needs to be sent along as well, so that the printer can shoot it on a copy camera (the old-fashioned way to make negatives); in that case, the artwork needs to be exactly as you want it to print — i.e., “camera-ready.”

CMYK

Cyan, Magenta, Yellow and Black — the ingredients of four-color process printing. To print properly, all of the colors you use in your design (whether in Photoshop, Illustrator, or Quark) must be designated as CMYK colors (not RGB colors). If you pick a color from the Pantone list, and you’re working on a four-color project, you must check the “Process Separation” box to make sure it separates and prints properly.

coated paper

Paper made with a surface coating, which allows for maximum smoothness and more accurate printing. Coated papers, which are available in a range of finishes from dull to matte to gloss, are almost always the best choice for four-color process printing.

color proof

For spot-color projects, most printers simply require b&w laser proofs of the design, which you can make yourself. However, for four-color projects, they’ll generally require an accurate color proof (sometimes called a “match print”), which you’ll need to purchase from a service bureau. Color proofs can be expensive, so be sure to take that into account when bidding for a project.

color separation

In four-color process printing, the technique of dividing continuous-tone color images into four film halftones ready for stripping, proofing, and platemaking. Or, in a spot-color project, the technique of producing a separate negative for each spot color. (In Quark, you can make b&w laser separations for each of your spot colors to make sure that the design is set up correctly before you send it off to the printer.)

contact print

In cases when a blueline fails to indicate just how light or dark a critical image will print, you may want to request a contact print — a b& w photograph made from a negative in contact with light-sensitive paper.

crop marks

Tiny lines, usually at the corners of a design, which indicate where the printer should trim. Quark can produce automatic crop marks along the edges of your document, but in some cases (such as laying out a page of business cards) you may want to create them yourself. Just be sure they don’t come in contact with the design.

continuous-tone

Artwork that is not made up of printable dot pattern (halftone). An original photograph is a continuous-tone image.

die cut

To cut irregular shapes in paper using a metal die. Die-cutting can add considerable expense to a project.

digital printing

As an economical alternative to four-color process printing, small quantities of a design are sometimes output directly on a color laser printer or other digital printing device, eliminating altogether the need for film, plates, and printing ink.

dot gain

Phenomenon of halftone dots printing larger on paper than they are on films or plates, reducing detail and lowering contrast in the final printed piece. The type of ink and paper can affect the amount of dot gain dramatically. Newsprint suffers from heavy dot gain due to the coarseness of the paper fiber.

DPI

Dots per inch. Refers to the output resolution of a device such as a laser printer, ink jet printer, or imagesetter . Devices can range from low resolution (300 dpi laser printer) to very high (2400 - 4000 dpi imagesetter). Generally, the higher the resolution, the higher the quality of the output.

drum scanner

A professional-quality scanner in which the copy is mounted on transparent drums. Drum scanners are considerably more expensive than flatbed scanners, but are generally preferred for four-color work because they have a higher resolution (8 - 12 bits per pixel) and a dynamic range from 3.5 to 4.0. However, some flatbed scanners have increased their resolution to 8 bits per pixel and their dynamic range to over 3.0. So the designer willing to invest in a really good flatbed scanner may be able to avoid having to pay a service bureau.

dummy

A preliminary layout showing the position of illustrations and text, or the arrangement of printed pages, as they are to appear in the final piece. A simple dummy of your design can prevent many costly errors.

emboss

To press an image into paper so that it lies above the surface.

film

The material produced by prepress houses to allow a printing plate to be made for press. It takes the form of thin sheets of plastic with a negative image of the artwork on it. Film can hold a higher resolution than paper; some imagesetters have resolutions as high as 4000 dpi.

four-color process printing

Technique of printing that uses process colors — cyan, magenta, yellow, and black — to simulate full-color images. If you examine four-color images with a magnifying glass or photographic loupe you’ll see the individual halftone dots that were used to create them.

FPO

For Position Only. The abbreviation designers use to warn printers that an element in the layout isn’t actually supposed to print. It is used most often to designate low-resolution images positioned in a document to be replaced later with a higher-resolution version of the same image. (Designers use this trick so their layout programs won’t be slowed down by memory-intensive, high-resolution graphics.)

halftone

Thousands of dots that together create the illusion of shading or of a continuous-tone image. Halftone dots are different than the digital dots in “dots per inch.” One halftone dot may be composed of many digital dots.

hard copy

Some old-fashioned printers (especially screen printers) aren’t equipped to handle digital designs. They need to have a separate paper print (such as a b&w laser print) of each color in your design. They’ll shoot these paper prints on a copy camera to make film for printing.

imagesetter

Professional-quality laser output device using photosensitive paper or film. Imagesetters have higher resolutions than ordinary laser printers because they create dots from chemical crystals in emulsion instead of from toner.

laser proof

Printers generally expect two kinds of proof for a spot-color design: a composite b&w laser proof (which prints all the colors of your design on a single page), together with a b&w laser separation for each of the colors in your design. (You can produce laser separations in Quark by choosing “Separation On” in the Print Dialogue box.)

LPI

Lines Per Inch. Measure of screen ruling expressing how many lines of halftone dots are contained in one inch. The higher the LPI (line screen) of a publication, the greater the sharpness of its images. Compare the photos in a newspaper (generally around 85 lines per inch) with the photos of a glossy magazine (about 150 lines per inch). It is possible to run out an image with a high resolution (dpi) and a low line screen (lpi). To understand this paradox, use the Page Setup dialogue box in Quark to create a coarse 60 lpi b&w laser print of a high-resolution 300 dpi photograph.

mechanical binding

for notebooks and other types of books which must open flat. The sheets are punched with a series of round or slotted holes. Then wire or plastic coils or rings are inserted through the holes. In designing a publication for mechanical binding, allowance must be made in the gutter (inner margin) of the book for the punched holes. Spiral-bound notebooks are an example of mechanical binding.

OCR

Optical Character Recognition. Special software which can “read” a scan of printed text and convert it to editable type (rather than pixels). Many scanners come packaged with OCR software.

offset lithography

The official name for the printing process we use. The term “offset” refers to the use of an intermediate blanket cylinder to transfer an image from the plate to the paper; “lithography” literally means “stone printing,” because before the invention of printing plates, images were printed from a smooth slab of limestone.

perfect binding

Economical method of binding paperback publications which eliminates the expense of sewing. After the signatures are collated, the backs are ground off, leaving a rough surface. An adhesive is applied, a special lining is put over the backbone, and the cover is glued into place. The phone book is an example of this.

plate

Piece of paper, metal, plastic, or rubber carrying an image to be reproduced using a printing press. Produced photographically using film negatives to control the exposure of the plate to a high-intensity light. Exposed areas of the plate hold ink on the press, thereby reverting the negative image back into a positive.

platesetter

A device which outputs your design directly onto a printing plate, eliminating the intermediate steps of making film negatives, stripping, and burning plates.

PostScript type

PostScript is a page description language developed by Adobe to create purely text-based equivalents of graphics or type. PostScript (or Type 1) typefaces are preferred by service bureaus and printers; TrueType fonts, which use a different logical system to describe type, have to be converted to PostScript fonts or rasterized before they can be output, and this can cause unnecessary problems.

prepress

Camera work, color separating, stripping, platemaking and other services provided prior to printing. Typically used these days to refer to the process of having film run out to an imagesetter.

printer's spread

Although most service bureaus and printers have the capacity to rearrange the pages of a document design to reflect the order in which they’ll actually be printed, sometimes the designer will be asked to do this him/herself. That’s what they mean if they ask you for a “printer’s spread.” So it’s important for every designer to know how to calculate the arrangement of pages (or “imposition”) which will be required for a document of a particular length.

register

To place printing properly with regard to the edges of the paper and other printing on the same sheet. Items out of register seem to be out of place, skewed, or blurry.

registration marks

Crosses or other targets which appear in precisely the same position on each color separation. They are used to register each color for stripping and printing. (When making your own b&w laser proofs, you can opt for registration marks in the Print Dialogue Box.)

resolution

In electronic imaging, the quantification of image quality using the number of dots per inch. For high-quality four-color process printing, imagery with a resolution of 300 dpi (or higher) is the norm.

RGB

Red, Green, and Blue. The primary additive colors used in scanners and computer monitors. Photoshop runs most efficiently when images are designated as RGB Mode, but they must be converted to CMYK Mode before they can be printed.

RIP

Raster Image Processor. A combination of computer software and hardware that controls the process of digital printing or output by calculating the bit maps of images and instructing printing devices to create the images. Most PostScript systems use a hardware RIP built into the printer.

saddle-stitched

The simplest and most inexpensive type of binding. The booklet is placed on a saddle beneath a mechanical stitching head and staples are forced through the spine or backbone of the booklet. Most booklets, programs, and catalogues are saddle-stitched.

side-stitched

Side-stitching is used when the bulk of the publication is too great for saddle-stitching. The sections are collated, and then placed flat under a stitching head. Side-stitched books cannot be opened completely flat and often have glued-on covers.

score

To indent a mark in the paper with a string or rule so that it can be more easily folded.

service bureau

A business devoted to prepress (e.g., making drum scans, outputting film, or making color proofs) and digital printing services. Sometimes called a “prepress house.” Nowadays, service bureaus are a rarity, since most printers have their own in-house prepress department.

sheet-fed press

Large publications such as newspapers are produced on web (offset) presses, which print on giant spools of paper. Smaller jobs, which can be printed one sheet at a time, are run on a sheet-fed (offset) press.

signature

In printing and binding, the name given to a printed sheet after folding. A typical signature might include as many as 16 or even 32 pages.

spot color

An ink that is specially mixed to match a pre-chosen hue (generally a Pantone color). Spot colors tend to be brighter and more vibrant than their process-color counterparts. Many spot colors are unproduceable in process color, because process color has a more limited color range or “gamut.” Fluorescents and metallic colors, for example, can only be produced with spot color.

stripping

The assemblage of film for platemaking. Stripping involves correcting flaws in film, assembling films into forms, and making sure that everything registers correctly.

SWOP

Specifications for Web Offset Printing. An abbreviation for the industry standards of ink color and dot gain tolerance. You can choose the SWOP option in Photoshop to specify that your image will be output according to the standards of offset lithography, thereby avoiding unnecessary dot gain and color shifts.

trapping

Trapping is the extension of a color so that it overlaps an adjacent color. The purpose of trapping is to compensate for gaps that might appear between colors due to misregistration on press. Four-color jobs and jobs created in Quark rarely need special trapping — so don’t mess with those settings unless the printer asks you to. However, Quark will not trap imported images. So items created in illustration programs often do require special trapping before they’re brought into Quark. Typically this will involve adding a 1-point stroke to light-colored objects, and designating that stroke to “overprint,” so that there will be a slight overlap of your light-colored shapes wherever they meet your darker shapes.

trim size

The final dimensions of your design after it has been printed and cut.

web press

A press specially designed for large publications such as newspapers, which prints on huge rolls of paper (rather than separate sheets).

WYSIWYG

What You See Is What You Get. Means that what you see on the computer screen is generally the same as what appears on the hard copy or film. Pronounced “wizzywig.” As every experienced designer knows, no software program is truly WYSIWYG. Variations in color calibration, color gamut, and resolution of your monitor and your printing device create inevitable discrepancies between what you see and what you get.

We hope this guide to printing terminology has been helpful. If you would like additional guidance, help with solicitation of print bids or expert assistance with your graphic design or web design projects, please call Flywheel Design at 1.800.549.8628 We have experience providing annual report design for Raleigh businesses, along with, magazine design, newsletter design, catalog design, brochure design, poster design, product labels, packaging design, signage, billboard design and trade show displays, logo design, business cards and stationery.

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