Helpful Information

Paper Weight Comparison Chart


Accordion fold

In binding, a term used for two or more parallel folds which open like an accordion.


Adobe software that embodies the PDF format.

Against the grain

Folding or feeding paper at right angles to the grain direction of the paper.

Anti-offset or set-off spray

In printing, dry spray of finely powdered starch used on press to prevent wet ink from transferring from the top of one sheet to the bottom of the next sheet. This also separates the sheets on a micro level so oxygen can react with the ink to enhance ink drying.

Aqueous Coating

A water-based coating that is applied like varnish to protect the printed surface. Aqueous coating can be applied in-line or off-line.

Backing up

Printing the reverse side of a sheet already printed on one side.

Barrel fold

In binding, two or more simple folds in which the outer edges of the pages are folded in toward each other.


The use of thread, staples, wire, glue, or other agents to collect sections or signatures into books, brochures and pamphlets.


In offset printing, a rubber-surfaced fabric which is clamped around a cylinder, to which the image is transferred from the plate, and from which it is transferred to the paper.


An extra amount of printed image which extends beyond the trim edge of the sheet or page.

Blind embossing

A design which is stamped without metallic leaf or ink, giving a bas-relief effect.

Book paper

A general term for coated and uncoated papers. The basic size is 25″x38″.

Calibrate (color calibrate)

To fix, check or correct the gradation of color on a color monitor.


The thickness of paper, usually expressed in thousandths of an inch (mils). In board, however, it is expressed as “points”.

Chokes and spreads

Overlap of overprinting images to avoid color or white fringes or borders around image detail. Called trapping in digital imaging systems.

CMYK (Cyan, Magenta, Yellow, Black)

The subtractive process colors used in color printing. Black (K) is added to enhance color and contrast.

Coated paper

Paper having a surface coating which produces a smooth finish. Surfaces vary from eggshell to glossy.


An emulsion, varnish or lacquer applied over a printed surface to protect it.


In binding, the gathering of sheets and signatures.

Color correction

Any method such as masking, dot-etching, re-etching and scanning, used to improve color.

Color separation

In photography, the process of separating color originals into the primary printing color components in negative or positive form using RGB filters.

Color workflow

The production workflow in a color managed environment.

Continuous tone

An image which contains gradient tones from black to white.


The tonal gradation between the highlights, middle tones and shadows in an original or reproduction.

Cover paper

A term applied to a variety of papers used for the covers of catalogs, brochures, booklets and similar pieces.


Sometimes called “push out,” it is the distance margins shift when paper is folded and/or inserted during finishing. The amount of creep will vary depending on both the number and thickness of the sheets and must be compensated for during layout and imposition.


To eliminate portions of the copy, usually on a photograph or plate, indicated on the original by cropmarks.


An image that straddles two pages or runs across a spread. Critical for bindery work, particularly when the crossover image is created from two separate pages. Not all bindery methods area good candidates when crossovers need to match up exactly.


In diecutting, a sharp-edged knife, several thousandths of an inch lower than the cutting rules in a die, made to cut part way into the paper or board for folding purposes.


Hue of a subtractive primary and a 4-color process ink. It reflects or transmits blue and green light and absorbs red light.


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


In photography, a photoelectric instrument which measures the density of photographic images, or of colors. In printing, a reflection desitometer is used to measure and control the density of color inks on the substrate.


The process of using sharp steel rules to cut special shapes for labels, boxes and containers, from printed sheets. Diecutting can be done on either flatbed or rotary presses. Rotary diecutting is usually done inline with the printing.

Digital color proof

A color proof produced from digital data without the need for separation films.

Digital plates

Printing by plates that can be exposed by lasers or other high energy sources driven by digital data in a platesetter.

Digital printing

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


Smallest screening element. The fineness of a halftone screen is measured in ‘lines per inch’ or lpi. In AM screening the dots vary in size. In FM screening the dots are all the same size.

Dot gain

In printing, a defect in which dots print larger than they should, causing darker tones or stronger colors.

Dots Per Inch (dpi)

Number of dots in a line screen per inch.A measure of the resolution of a screen image or printed page.


Sending information to another computer or to an output.


A preliminary layout showing the position of illustrations and text as they are to appear in the final reproduction. A set of blank pages made up in advance to show the size, shape, form and general style of a piece of printing.


In photomechanics, a term for a two-color halftone reproduction from a one-color photograph.

Dynamic range

Density difference between highlights and shadows of scanned subjects.

Embossed finish

Paper with a raised or depressed surface resembling wood, cloth, leather or other pattern.


Impressing an image in relief to achieve a raised surface; either overprinting or on blank paper (called blind embossing).


In printing presses, the section that separates the sheets and feeds them in position for printing.

Felt side

The smoother side of the paper for printing. The top side of the sheet in the paper manufacturing.

Finish Surface

Texture of a paperstock.

Flush cover

A cover that has been trimmed to the same size as the inside text pages.

Foil Stamping

Printing method that releases foil from its backing when stamped with a heated plate or die.

Folding dummies

A mock-up of the job using the actual paper trimmed and folded to exact specifications.


To bend or crease a sheet of paper to create a printed or bound document.


The page number.


In composition, a complete assortment of letters, numbers, punctuations, etc., of a given size and design.

Form rollers

The rollers, either inking or dampening, which directly contact the plate on a printing press.

Fountain solution

In lithography, a solution of water, a natural or synthetic gum and other chemicals used to dampen the plate and keep non-printing areas from accepting ink.

FPO (For Position Only)

In digital imaging, typically a low-resolution image positioned in a document to be replaced later with a higher resolution version of the same image.


In papermaking, the direction in which most fibers lie which corresponds with the direction in which the paper is made on a paper machine.

Gray Balance

The dot values or densities of cyan, magenta and yellow that produce a neutral gray.

Gray scale

A strip of standard gray tones, ranging from white to black, placed at the side of original copy during photography to measure tonal range and contrast (gamma) obtained.

Gripper edge

The leading edge of paper as it passes through a printing press. Also, the front edge of a lithographic or wraparound plate secured to the front clamp of a plate cylinder.

Gripper margin

Unprintable blank edge of paper on which grippers bear, usually 1/2″ or less.


In sheetfed printing presses, metal fingers that clamp on paper and control its flow as it passes through.


The blank space or inner margin from printing area to binding.


The reproduction of continuous-tone images, through a screening process, which converts the image into dots of various sizes and equal spacing between centers (AM screening), or dots of equal size with variable spacing between them (FM screening).

Halftone dots

The smallest unit that a screen consists of. All tones in print, both photographs and illustrations, are based on halftone dots.


In offset lithography, spots or imperfections in the printing due to dirt on the press, dried ink skin, paper particles, etc.

Hi-res (high resolution)

An image that has sufficient sharpness (measured by the number of pixels per inch) to make it suitable for print reproduction.


In color, the main attribute of a color which distinguishes it from other colors.


In digital imaging, a generic term that applies to film-output devices for type and graphics. The difference between an imagesetter and a typesetter is in the format of the data that has been converted from discrete-character raster lines to raster data using bitmaps.


In image assembly, the positioning of pages on a signature so that after printing, folding and cutting, all pages will appear in the proper sequence.

Impression cylinder

In printing, the cylinder on a printing press against which the paper picks up the impression from the inked plate in direct printing, or the blanket in offset printing.

Ink coverage

The amount of ink added in the printing process. Also describes the maximum allowed amount of each component color on a certain paper in a printing process. Expressed as a percent.

Ink fountain

In printing presses, the device which stores and supplies ink to the inking rollers.

Ink-jet printing

In digital printing, a plateless printing system that produces images directly on paper from digital data using streams of very fine drops of dyes which are controlled by digital signals to produce images on paper.


To align sheets of paper into a compact pile.


Type or images that reverse out of a solid or tint, allowing the paper to show through. Also called reverse.


A plastic film bonded by heat and pressure to a printed sheet for protection or appearance. Lines Per Inch (lpi) The number of lines of output per inch; for example, a halftone of 85 lines per inch is lower resolution than a halftone of 120 lines per inch; lines per inch, lpi, line screen and screen frequency are all synonymous.

Lithographic Offset Printing (litho)

Printing method using plates whose image areas attract ink and whose non-image areas repel ink. Non-image areas may be coated with water or a coating, such as silicon, to repel ink.


A magnifying lens held close to the eye to examine printing. The most common is an eight-power, which enlarges an image by a factor of eight.


Hue of a subtractive primary and a four-color process ink. It reflects or transmits blue and red light and absorbs green light.


In printing, all work done to set up a press for printing.

Match color

A custom-mixed ink color that exactly matches a specified color. Typically chosen from numbered color matching systems. Also called spot color.

Matte finish

Dull paper finish without gloss or luster.

Metallic Inks

Inks containing metal powder that have a shiny reflective appearance.


The tonal range between highlights and shadows of a photograph or reproduction.


A print phenomenon in which the component colors don’t print directly on top of each other (i.e. in register).


A booklet or catalog bound on the shorter dimension.


In printing, the process of using an intermediate blanket cylinder to transfer an image from the image carrier to the substrate. Short for offset lithography.


That property of paper which minimizes the show-through of printing from the back side or the next sheet.

Opaque ink

An ink that conceals all color beneath it.

Overhang cover

A cover larger in size than the pages it encloses.


Double printing; Printing over an area that already has been printed.


In printing, copies printed in excess of the specified quantity.

PDF (Portable Document File)

PDF is a universal electronic file format, modeled after the PostScript language and is device-and resolution-independent. Documents in the PDF format can be viewed, navigated and printed from any computer regardless of the fonts or software programs used to create the original.

Perfect Binding

A method of binding which uses adhesive to hold signatures or pages together.

Perfecting press

A printing press that prints both sides of the paper in one pass through the press.


Printer’s unit of measurement used principally in typesetting. One pica equals approximately 1/6 of an inch.


In printing inks, the fine solid particles used to give inks color, transparency or opacity.


Short for “picture element.” A pixel is the smallest resolvable point of a raster image. It is the basic unit of digital imaging. Pixels per inch (ppi) States the resolution of images, monitors and scanners.

Plate cylinder

The cylinder of a press on which the plate is mounted.


An image recorder which images directly on plate material. Platesetters currently available use lasers to expose or image paper, polyester or aluminum plates.

PMS (Pantone Matching System)

Color charts that have over 700 preprinted color patches of blended inks, used to identify, display or define special colors.


Printer’s unit of measurement, used principally for designating type sizes. There are 12 points to a pica; approximately 72 points to an inch.

Position proof

Color proof for checking position, layout and/or color breakout of image elements.


In digital prepress, the test used to evaluate or analyze every component needed to produce a printing job. Preflight confirms the type of disk being submitted, the color gamut, color breaks, and any art required (illustrations, transparencies, reflective photos, etc.) plus layout files, screen fonts, printer fonts, EPS or TIFF files, laser proofs, page sizes, print driver, cropmarks, etc.

Press proofs

In color reproduction, a proof of a color subject made on a printing press, in advance of the production run.

Process colors

In printing, the subtractive primaries – yellow, magenta and cyan, plus black in four-color process printing.


A term for a four-color halftone reproduction from a one-color photograph.

Raster image processor (RIP)

In digital imaging, a combination of computer software and hardware that controls the printing process by calculating the bitmaps of images and instructing a printing device to create the images. Most PostScript systems use a hardware RIP built into the printer.


Five hundred sheets of paper.


In printing, fitting of two or more printing images in exact alignment with each other.

Register marks

Crosses or other targets applied to original copy prior to photography. Used for positioning films in register, or for register of two or more colors in process printing.


In electronic imaging, the quantification of printout quality using the number of dots per inch.


Images reproduced by printing ink around their outline, thus allowing the underlying color of paper to show through and form the image. Also called knockout.

RGB (red, green and blue)

The primary additive colors used in display devices and scanners. Commonly used to refer to the color space, mixing system or monitor in color computer graphics.

Right-angle fold

In binding, a term used for two or more folds that are at 90 degree angles to each other.

Saddle stitch

In binding, to fasten a booklet by wiring it through the middle fold of the sheets. Also called saddle wire.


Determining the proper size of an image to be reduced or enlarged to fit an area.


An electronic device used in the making of color and tone-corrected separations of images.


To impress or indent a mark in the paper to make folding easier.


A method of printing that breaks up continuous-tone images into printable dots.

Screen angles

In color reproduction, angles at which the halftone screens are placed in relation to one another, to avoid undesirable moiré patterns. A set of angles often used is – black 45 degrees, magenta 75 degrees, yellow 90 degrees, cyan 105 degrees.

Screen printing

A printing method used for large formats, such as billboards and hard print carriers, such as steel signs. The printing form consists of a finely woven cloth that lets through printing ink and is tightened to a frame. The non-printing surfaces are covered so that the ink cannot get through the cloth.

Screen tints

Color generated by dots instead of solid ink coverage.


In offset lithography, a film of ink printing in the non-image areas of a plate where it should not print.

Self cover

A cover of the same paper as inside text pages.


In presswork, when the ink of a printed sheet rubs off or marks the next sheet as it is being delivered. Also called offset.


The darkest parts in a photograph, represented in a halftone by the largest dots.


To decrease in color strength, as when halftone dots become smaller; opposite of dot spread or dot gain.


Printing from stacks of sheets that feed one at a time through the press.


To print one side of a sheet of paper with one plate then turn the sheet over and print the other side with another plate using same gripper and opposite side guide.


In image assembly and layouts, the center or gutter margin is varied according to the position of the page in the signature and the bulk of the paper.


In printing, the undesirable condition in which the printing on the reverse side of a sheet can be seen through the sheet under normal lighting conditions.

Side guide

On sheetfed presses, a guide on the feed board to position the sheet sideways as it feeds into the front guides before entering the impression cylinder.


A method of common binding where the folded signatures or pages are stitched along the side near the gutter margin. The pages will not lie flat.


In printing and binding, the name given to a printed sheet after it has been folded.


A platform support for a pile of cut sheets of paper.

Spiral binding

A book bound with wires in spiral form inserted through holes punched along the binding side.

Spot color

Printing inks of special colors, for example from the color matching systems and swatch books. Generally used as a complement to black or to achieve an exact color four-color inks cannot provide. Mixed according to a recipe. Also called match color.

Spot varnish

Varnish applied to specific areas of a sheet, as compared to flood varnish.


A technique of slightly enlarging the size of an image to accomplish a trap with another image.Also, a two-page arrangement of copy.


A proofreader’s mark, written in the margin, signifying that copy marked for corrections should remain as it was.


Paper or other material to be printed.


In printing inks, the property of cohesion between particles; the separation force of ink needed for proper transfer and trapping on multicolor presses.A tacky ink has high separation forces and can cause surface picking or splitting of weak papers.

Tagged image file format (TIFF)

A file format for graphics suited for representing scanned images and other large bitmaps. TIFF is a neutral format designed for compatibility with all applications. TIFF was created specifically for storing grayscale images, and it is the standard format for scanned images such as photographs- no called TIFF/IT.


Printing method using colorless resin powder that takes on the color of the underlying ink to create a raised printed surface.


Various even tone areas (strengths) of a solid color created by dots rather than solid ink coverage. Also called screen tints.


In digital printing, imaging material also called digital inks, used in plateless printing systems like electrophotography, magnetography, ion or electron deposition and laser printers. In inks, dye used to tone printing inks, especially black.

Transparent ink

A printing ink which does not conceal the color beneath. Process inks are transparent so that they will blend to form other colors.


In printing, the ability to print a wet ink film over previously printed ink. Dry trapping is printing wet ink over dry ink. Wet trapping is printing wet ink over previously printed wet ink. In prepress, refers to how much overprinting colors overlap to eliminate white lines between colors in printing.

Trim marks

In printing, marks placed on the copy to indicate the edge of the page.


A term for a three-color halftone reproduction from a one-color photograph, usually using two blacks and a gray.

UCR (UnderColor Removal)

In process multicolor printing, color separation films are reduced in color in neutral areas where all three colors overprint and the black film is increased an equivalent amount in the areas. This improves trapping and can reduce makeready and ink costs.

Uncoated stock

Paper that has not been coated. There are varying degrees of quality with the highest being Writing, Text and Cover papers.

Unsharp masking

Technique of adjusting dot size to make a halftone or separation appear in better focus. Also called edge enhancement and peaking.


In printing, two-up, three-up, etc., refers to imposition of material to be printed on a larger size sheet to take advantage of full press capacity.

UV inks

In printing, solventless inks that are cured by UV radiation. They are used extensively in screen printing, narrow web letterpress and flexographic printing.

Vellum finish

In papermaking, a toothy finish which is relatively absorbent for fast ink penetration.


An illustration in which the background fades gradually away until it blends into the unprinted paper.


In printing inks, a broad term encompassing the properties of tack and flow.

Warm color

In printing, a color with a yellowish or reddish cast


The process of cleaning the rollers, form or plate, and sometimes the ink fountain of a printing press.

Waterless printing

In offset, printing on a press using special waterless plates and no dampening system.


A roll of paper used in web or rotary printing.

Web press

A press which prints on a roll of paper.

Wire-o binding

A continuous double series of wire loops run through punched slots along the binding side of a booklet.

Wire side

In papermaking, the side of a sheet next to the wire in manufacturing; opposite from felt or top side.

With the grain

Folding or feeding paper into a press with the grain of the paper parallel to the blade of the folder or the axis of the impression cylinder.


To print one side of a sheet of paper, then turn it over from gripper to back using the same side guide and plate to print the second side.


To print one side of a sheet of paper, then turn it over from left to right and print the second side using the same gripper and plate but opposite side guide.