Printing Terminology: A Glossary for Label, Sticker and Emblem Buyers

Printing terminology is the shared vocabulary that describes how artwork is prepared, how colour is measured, how a substrate is printed and how the printed sheet is cut and finished. For a buyer of labels, stickers and emblems, roughly sixty terms cover almost every line on a quotation and every comment on a proof, even though the print industry uses several hundred. This printing glossary defines those terms one at a time, in the order a print project actually moves: file preparation, colour, printing technique, materials and finishing, cutting, then quantity and production. Where a term is governed by a published standard, the standard number is given, because most collections of common printing terms define these words from habit rather than from the document that fixes their meaning.

The entries below are written for people who specify self-adhesive labels, domed stickers, soft PVC emblems and metal plates, so this is a working print terminology reference rather than a general glossary of printing terms. Bookbinding vocabulary such as perfect binding, spine and gutter is left out, because it belongs to brochure work rather than to converting, and the key terms of large format printing appear only where they overlap with label production. Every definition stands on its own, so the glossary can be read end to end or used to check a single word before a purchase order goes out.

Artwork and file preparation terms

Artwork

Artwork is the supplied design file from which the printing plate, screen or digital press image is generated. It carries the graphics, text, barcodes and the geometry that tells the machine where the printed material ends. A print process cannot correct a fault that already exists in the artwork, which is why most production delays start here.

Bleed

Bleed is the artwork that extends beyond the finished edge so that no unprinted sliver appears if the cut wanders. It exists because every cutting operation has a mechanical tolerance. The amount of bleed is set by the individual printer’s file specification rather than by any international standard, so it should always be read off the supplier’s template.

Trim and trim line

The trim line is the intended final edge of the printed item, and to trim is to cut the printed sheet down to that edge. On a label the trim line is the same line the cutting die follows. Anything that must survive to the final print has to sit inside it.

Safe area

The safe area is the zone inside the trim line where text, logos and barcodes are guaranteed to remain after cutting. It absorbs the same registration tolerance that bleed absorbs, but from the opposite direction. Barcodes also need their own clear margin, called the quiet zone, which sits inside the safe area.

Cut path

A cut path, also called a cut contour, is a vector line in the artwork that tells the cutter or plotter exactly where to travel. It is placed on its own named spot colour layer so that the RIP treats it as a cutting instruction and not as printed ink. Files for self-adhesive labels supplied on a roll normally need one closed cut path per label, with no open ends or duplicated nodes.

Crop marks and registration marks

Crop marks are short lines outside the trim area that show the cutter where the finished edge falls. Registration marks are separate targets printed in all colours at once so that each printing plate can be aligned against the others. Misaligned registration marks are the usual visible sign of a press setup problem.

Vector and raster

Vector artwork is built from mathematical paths and can be scaled to any size without loss, while raster artwork is built from a fixed grid of pixels. Logos, text and cut paths should be vector. A printed image such as a photograph is necessarily raster, which is why its resolution has to be checked at final size.

Rasterisation and RIP

Rasterisation is the conversion of a page description into the grid of addressable dots the output device can actually mark. The software that performs it is the raster image processor, or RIP, and it also applies colour conversion, screening and trapping. Two RIPs fed the same file can produce visibly different output, which is one reason a proof is generated from the same RIP as the production run.

DPI (dots per inch)

DPI states how many dots per inch a device addresses or an image supplies, and it is a measure of sampling density rather than of visible sharpness. A raster image is judged at its final printed size, not at the size it happens to open on screen. Doubling the placed size of a photograph halves its effective DPI.

LPI and how it differs from DPI

LPI, or lines per inch, is the screen ruling of a halftone, meaning how many rows of halftone dots occupy an inch. DPI describes the device grid; LPI describes the halftone structure built on that grid, so a press running a coarse screen ruling gains nothing from a very high DPI file. Screen ruling is one of the process control parameters covered by ISO 12647-2 for offset lithographic processes.

PDF/X

PDF/X is a family of constrained versions of the portable document format defined by the ISO 15930 series for exchanging print-ready data between a print buyer and a print producer. PDF/X-4 is specified in ISO 15930-7 and allows live transparency and colour management, while PDF/X-6, in ISO 15930-9:2020, is based on PDF 2.0. Every PDF/X file declares which conformance level it meets in its XMP metadata, so a preflight tool can verify the claim rather than guess.

Proof

A proof is a representation of the intended result supplied for approval before production begins. A soft proof is viewed on a calibrated monitor; a contract proof is a physical print made to simulate a defined printing condition and carries measurable colour tolerances. Approval closes the prepress printing stage, releases the job to press and normally transfers responsibility for the content to the buyer.

Step and repeat

Step and repeat is the layout operation that multiplies a single label design across the printed sheet or web at the pitch the cutting tool expects. It sets how many labels sit across the width and how much gap falls between them. Getting it wrong wastes material rather than spoiling the printed image.

Variable data

Variable data is content that changes from one printed item to the next, such as serial numbers, QR codes or batch identifiers. Digital printing handles it natively because each impression is generated independently. It is the standard method for numbered tamper-evident warranty seals and for asset labels that must be traceable.

Colour terms

CMYK and process colour

CMYK is the four-ink process model built from cyan, magenta, yellow and black, in which colours are reproduced by overlaying halftone dots of those four inks. It is the default for commercial printing in full colour because four printing plates and four process printing inks can approximate a very wide range of colours. The colour and transparency of the ink sets themselves are the subject of ISO 2846-1:2017, which tests inks on a laboratory printability tester against a defined substrate and deliberately does not specify which pigments a manufacturer must use.

Spot colour and Pantone

A spot colour is a single pre-mixed ink printed from its own unit, rather than simulated from cyan, magenta, yellow and black. Pantone is the best known proprietary matching system, and brand colours are usually specified as a spot reference so that they stay constant across print runs and substrates. Recording those references, together with the accepted deviation, is one of the jobs of a brand book.

RGB

RGB is the additive model used by screens, where red, green and blue light combine to form colour. It cannot be printed directly, so RGB artwork is converted to a printing colour space before output. Saturated RGB greens and blues frequently fall outside the printable gamut and shift noticeably when converted.

Gamut

Gamut is the range of colours a given device, ink set and substrate can actually reproduce. A colour that lies outside the gamut has to be mapped to the nearest reproducible value, which is where unexpected colour changes appear. Gamut is a property of the whole combination, so the same ink on a matt paper facestock and on a gloss film gives two different gamuts.

Colour profile and ICC profile

A colour profile is a data file that characterises how a device or a colour space renders colour, allowing values to be converted predictably between them. The ICC profile format is standardised as ISO 15076-1, based on the International Color Consortium specification, with the current edition published in 2025. Supplying artwork with an embedded profile is what makes a colour conversion repeatable rather than a matter of opinion.

Delta E

Delta E is a single number expressing the difference between a measured colour and its target in CIELAB terms, with smaller values meaning a closer match. Print specifications state acceptance as a maximum delta E, and CIEDE2000 is the modern formula used for that comparison. ISO 12647-7, the proofing part of the process control standard, is one of the few documents that fixes such limits numerically: in its 2007 edition it required the process colour solids on a contract proof to agree with the aim values within a CIELAB difference of 5, with the hue difference contributing no more than 2.5, and it capped the control wedge patches at a maximum difference of 6 with an average of 3.

Overprint

Overprint means one colour is printed on top of another instead of knocking a hole in the layer beneath it. Applied deliberately it saves a trapping problem, most often on small black text. Applied by accident it makes light elements disappear entirely on the final print, because they end up printed over a dark background rather than reversed out of it.

Trapping

Trapping is the deliberate slight overlap of adjoining colours so that a small registration shift on the printing press does not open a white gap between them. The amount is set in the RIP and depends on the print process, since flexography needs more trap than offset. It is a production safeguard, not a design effect.

Dot gain

Dot gain, more formally tone value increase, is the growth of a halftone dot between the file and the printed sheet, which makes mid-tones print darker than specified. It varies with substrate, ink and printing method, and it is compensated for in the RIP rather than in the artwork, so uncompensated dot gain shows up as a printing defect rather than as a design error. Tone value increase is one of the primary process control parameters defined in the ISO 12647 series.

White underbase

A white underbase is a layer of opaque white ink printed beneath the colours so that they stay vivid on a transparent or metallic substrate. Without it, the background shows through and the printed image looks washed out. It is specified as a separate layer in the artwork and is essential for stickers printed on transparent foil.

Printing techniques

The method of printing chosen for a job decides the cost structure, the minimum quantity and how much colour control is available. Four processes cover almost all printed products in this field, and each is defined below by what it physically does rather than by which printing companies favour it.

Digital printing

Digital printing produces each impression directly from the file, with no printing plate and no fixed setup. That makes short runs, on-demand printing and variable data economical and shortens lead times, at a higher cost per piece on long runs. It is the usual printing method for small quantities of full-colour labels.

Offset lithography

Offset lithography, usually shortened to offset printing or litho printing, transfers ink from a printing plate to a rubber blanket and from the blanket to the substrate, relying on the mutual repulsion of the ink and the damping solution. This traditional printing process gives very consistent colour on long print runs and remains the lithographic printing reference behind most colour standards. An offset press carries one unit per colour, so each additional spot colour adds a plate.

Flexography

Flexography is a relief printing method that prints from a flexible raised plate on a rotary press, usually web-fed, and it is the dominant type of printing for self-adhesive labels made on a roll. It inherits the relief principle from letterpress but uses a soft photopolymer plate and fast-drying printing inks instead of metal type, and its process control parameters are covered by ISO 12647-6. Printing, laminating, die cutting and slitting can all run in line on the same pass, which is why flexo dominates roll label work.

Screen printing

Screen printing forces ink through a stencilled mesh onto the printing surface, laying down a much thicker ink film than offset or digital. The heavier deposit gives strong opacity and durable solid colours, which is why it is still used for industrial nameplates and for opaque white on dark films. Fine detail and photographic gradation are its weak points.

UV curing

UV curing hardens ink or coating instantly by exposing it to ultraviolet light rather than letting a solvent evaporate. Because the film sets on contact with the lamp, it can be printed on non-absorbent plastics that would never dry conventionally. It is the reason most film labels can be printed and finished in a single pass.

Hot foil stamping

Hot foil stamping presses a heated die against a metallised foil carrier to transfer a thin metallic layer onto the printed material. The result is a genuinely reflective surface that no ink can imitate. The same tooling can be combined with embossing so that the foiled area is raised at the same time.

Materials and finishing

Facestock

Facestock is the top, printable layer of a self-adhesive material, the part that becomes the visible label. It may be paper or a film such as PVC, polypropylene or polyester, and the films used for printing are quoted by thickness without the adhesive and liner. The ORAFOL ORAJET 3551DT data sheet, for example, specifies a polymeric PVC facestock of 70 micron.

Liner

The liner, or release liner, is the siliconised backing that carries the label until it is applied and protects the adhesive in the meantime. It is a functional engineering component with its own specification, not packaging: the ORAJET 3551DT construction uses a double-sided PE-coated paper liner, siliconised on one side, at 143 g/m². Machine applicators depend on that liner behaving consistently, so changing it changes the running behaviour of the label.

Pressure-sensitive adhesive

A pressure-sensitive adhesive bonds when hand or roller pressure is applied, with no heat, water or solvent needed to activate it. It is classified as permanent, removable or repositionable according to how it behaves after application. The same facestock is routinely offered with several adhesives, and the adhesive is usually the component that decides whether a label survives its application.

Peel adhesion

Peel adhesion is the measured force needed to pull a label away from a surface, and it is the number that turns “strong adhesive” into something a buyer can compare. The industry reference method is FINAT Test Method FTM 1, which peels a 25 mm wide strip from float glass at 180 degrees at 300 mm per minute, reporting the result in newtons per 25 mm after a 20 minute and a 24 hour dwell. On that basis the ORAJET 3551DT adhesive is quoted at 18 N/25 mm after 24 hours.

Grammage and GSM

GSM is grammage, the mass of the paper used per unit area, expressed in grams per square metre. The measurement method is fixed by ISO 536, which defines grammage as mass per unit area and specifies a preferred test piece area of 50 000 mm² to 100 000 mm². Grammage describes weight, not thickness, so two papers at the same GSM can feel quite different.

Micron and caliper

Micron, or micrometre, is the unit used for the thickness of films and coatings, where grammage would say nothing useful. Caliper is the measured thickness of a sheet of paper or a laminate, quoted in microns or thousandths of an inch. Film label materials are specified in microns because their stiffness and conformability follow thickness rather than mass.

Monomeric and polymeric vinyl

Monomeric and polymeric describe the plasticiser system in a PVC film and therefore how much it will shrink and how well it conforms. Monomeric films are cheaper and suited to flat, short-life applications such as temporary large format printing, while polymeric films are more dimensionally stable and last longer outdoors. The distinction is explained in more detail in this guide to monomeric vinyl film.

Laminate

A laminate is a separate clear film bonded over the printed surface to protect it from abrasion, moisture and UV exposure. It is supplied in gloss, matt and textured finishes, and it adds measurable thickness and stiffness to the construction. Because it is a film rather than a coating, it also seals the printed image at its edges.

Varnish

Varnish is a liquid coating applied over the print and then dried or cured, giving a glossy or matt surface without adding a separate film. Spot varnish is applied only to chosen areas, usually to make a logo catch the light against a matt background. Varnish protects against handling and scuffing, but far less than a laminate does.

Doming

Doming is a finishing process in which a measured quantity of clear resin is deposited onto a printed self-adhesive label, where surface tension pulls it into a raised, lens-shaped dome before it cures. Polyurethane resin has largely replaced epoxy for this because it stays clear instead of yellowing, and the resulting domed 3D stickers are typically 2 to 2.5 mm high on small formats and 1.5 to 2 mm on larger ones. The cured layer acts as both a magnifying lens and an impact-resistant coating, and it is the defining feature of 3D epoxy labels.

Embossing and debossing

Embossing raises an area of the material above the surrounding surface using a matched pair of dies, and debossing presses it below. On paper and film the effect is purely tactile, while on metal it produces a permanent structural relief. Raised lettering on metal emblems is produced this way rather than printed.

Chrome and metallised film

A metallised film carries a vacuum-deposited metal layer that reflects light, so the substrate itself supplies the mirror effect rather than an ink. A chrome finish is the most reflective of these and behaves optically like polished metal. Printing on chrome stickers requires either transparent inks that let the metal show through or a white underbase where opacity is wanted.

Soft PVC

Soft PVC is a flexible plasticised compound moulded into a shaped, multi-level relief rather than printed flat. Colour comes from the compound itself, so it cannot fade off the surface, and the finished part is washable and abrasion resistant. It is the standard construction for soft PVC 3D rubber patches and similar moulded emblems.

Crease, fold and score

A crease is a compressed line pressed into the material so that it folds cleanly along a known path, and scoring is the shallow cut that does the same job on thicker stock. Without one, a fold cracks the coating and the printed image splits along the edge. Multi-page booklet labels on packaging depend on a correct crease as much as any brochure does.

Die cutting, kiss cutting and converting

Die cut

A die cut is a through-cut that passes through the facestock, the adhesive and the liner, separating the item completely from the surrounding web. The result is an individual piece with its own shaped backing. In everyday use the phrase also covers any cut made with a shaped tool rather than a straight blade.

Kiss cut

A kiss cut cuts through the facestock and adhesive but stops at the liner, leaving the backing intact so the label stays in place until it is peeled. It is what allows labels to be supplied on a continuous roll for hand or machine application, and what makes a multi-sticker sheet possible. The pressure is set so precisely that a kiss cut on a thin film construction is measured against the liner thickness, not against the total caliper.

Cutting die

A cutting die is the physical tool that makes the shape, either a flat steel-rule die pressed into the material or a rotary die that cuts against an anvil as the web runs. Rotary dies are faster and made for a specific shape and repeat length, so they carry a one-off tooling charge. Standard shapes usually run on existing tooling, which is why a rectangle with rounded corners is cheaper than a bespoke outline.

Matrix and weeding

The matrix is the waste skeleton of material left surrounding the labels after kiss cutting. Weeding is the removal of that waste, either stripped continuously on the press or picked out by hand on short runs. Whether the matrix is removed changes how the labels look on the sheet and how easily they can be picked up.

Transfer tape

Transfer tape, also called application tape, is a low-tack film laid over cut vinyl lettering or graphics so that every element can be lifted off the liner and applied in one operation, keeping the spacing intact. It is removed once the graphic is on the surface. It is a fitting aid, not part of the finished product.

Perforation

A perforation is a line of alternating cuts and uncut ties that lets part of the printed item be torn away cleanly by hand. On labels it creates tear-off coupons, return sections and detachable serial number tabs. The ratio of cut to tie decides whether it tears too easily or not easily enough.

Corner radius

Corner radius is the curvature applied to the corners of a rectangular label, quoted in millimetres. Rounded corners are specified because a sharp corner is the point where a label starts to lift and peel back in service. A radius of a few millimetres is enough to remove that failure point.

Slitting, rolls and sheets

Slitting cuts the printed web lengthways into finished roll widths after printing and die cutting. Whether labels are supplied on rolls or as sheets follows from how they will be applied: automatic applicators need rolls, while hand application often suits sheets. Roll orders also require a core diameter and a wind direction, which state how the label leaves the roll and matter to any machine that dispenses it.

Quantity, cost and production terms

MOQ

MOQ is the minimum order quantity, the smallest run a supplier will accept for a given product. It exists because setup work such as plate making, die tooling and colour matching is charged once regardless of how many pieces follow. MOQ varies by process, and it is usually lowest for digital printing and highest for anything needing a bespoke cutting die or moulding tool.

Print run

A print run is the number of pieces produced in a single continuous production, and it is the main driver of unit price. Setup cost is spread across the run, so doubling the quantity rarely doubles the price. Splitting one design across two separate print runs pays the setup twice.

Tooling cost

Tooling cost is the one-off charge for the physical tools a job needs, such as a cutting die, an embossing die or a mould. It belongs to the shape rather than to the order, so repeat orders of the same shape avoid it. Keeping a product family on one shared outline is the simplest way to control it.

Gang run

A gang run places several different designs on the same printing plate or sheet so they share one setup. It lowers the cost per design, but every design in the group is then locked to the same substrate, colours and schedule. Colour critical work is normally kept out of a gang run for that reason.

Lead time

Lead time is the interval between artwork approval and dispatch, and it starts at approval rather than at the order. Additional finishing steps such as lamination, doming or moulding add curing and handling time that cannot be compressed. Examples of complete production timelines are visible in these customer implementations.

Batch code and traceability

A batch or lot code identifies which production a given item came from, allowing a defect to be traced back to its materials and press conditions. On regulated goods it is printed as variable data rather than fixed artwork. It is a routine requirement on packaging labels and on chemical labelling.

Tolerance

Tolerance is the permitted deviation from a nominal value, whether in dimensions, position or colour. Every printing method and every cutting method has one, and a specification that omits tolerances simply leaves them to the supplier’s own defaults. Naming the tolerance that matters, such as a maximum delta E or a cut position limit, is what makes a specification enforceable.

Choosing how a label is cut

The cutting format is the single specification that most often gets confused when an order is placed, because die cut and kiss cut sound like alternatives when they in fact describe different depths of the same operation. The table below sets out what each option does and what it is normally used for.

Cut format	What the tool cuts	How it is supplied	Typically used for
Die cut (through cut)	Facestock, adhesive and liner	Individual pieces, each on its own shaped backing	Single decals, emblems, domed stickers
Kiss cut	Facestock and adhesive only, liner left intact	Continuous roll or sheet, matrix removed or left in place	Roll labels for applicators, multi-sticker sheets
Perforation	A broken line through the material	Sheet or roll that tears along the line	Tear-off tabs, coupons, detachable serial sections
Guillotined to size	Straight cuts only, no shaped tool	Rectangular sheets or blocks	Plain rectangular labels where no tooling is wanted

Frequently asked questions

• Do warning and safety labels use different terminology?

  The production vocabulary is identical, but the content is additionally governed by symbol and format standards rather than by print specifications alone. Safety signs and labels follow the graphical symbols defined in ISO 7010, and chemical products carry their own pictogram rules. That makes the artwork approval step on warning stickers a compliance check as well as a proofing check.

• Which printing terms matter most when ordering domed stickers?

  Facestock, cut path, die cut, dome height and lead time carry the most weight, because doming is applied after printing and cutting and cannot correct anything decided earlier. The facestock determines how the resin sits and how the sticker performs outdoors, the cut path defines the outline the dome has to fill, and the curing step lengthens the lead time. Colour should be agreed on a proof before resin is applied, since the cured dome cannot be reworked.

• Does GSM apply to self-adhesive label materials?

  GSM applies to the paper components of the construction, most usefully to the liner, which is specified in grams per square metre because its strength and machine behaviour follow its mass. Film facestocks are specified in microns instead, since thickness rather than weight governs how they conform and cut. A full label specification often quotes both, one for the face material and one for the liner.

• What does a delta E tolerance of 2 actually mean?

  It means the printed colour must sit within two CIEDE2000 units of the agreed target when measured, which is a difference most observers would struggle to see side by side. Delta E is a measurement, not an opinion, so it only works as an acceptance criterion when the target values, the measurement conditions and the formula are all named in the specification. ISO 12647-7 shows the approach in practice by fixing numerical limits for a contract proof.

• Is a kiss cut the same as a die cut?

  No. A die cut passes through the facestock, the adhesive and the liner so the piece comes away completely, whereas a kiss cut stops at the liner so the label remains on its backing. Both use a shaped tool, so the difference is the depth setting rather than the tooling, and it decides whether the order arrives as loose pieces or as a roll or sheet.

Sources

The definitions above are taken from published standards and from manufacturers’ technical data sheets rather than from secondary summaries, because most printing terms are used loosely until a standard fixes them. Standards documents supply the colour tolerances, the measurement methods and the file format definitions; material data sheets supply the construction figures for facestock, liner and adhesive. The five sources below carry the specific numbers quoted in this glossary.

• ISO 12647-7, Graphic technology, process control for the production of halftone colour separations, proof and production prints, Part 7: Proofing processes working directly from digital data, for the contract proof colour tolerances.
• ISO 536, Paper and board, determination of grammage, for the definition of grammage and the test piece area.
• ISO 2846-1:2017, Graphic technology, colour and transparency of printing ink sets for four-colour printing, for how process ink sets are specified and tested.
• ORAFOL ORAJET 3551DT technical data sheet, for the facestock thickness, liner grammage and adhesive figures.
• FINAT Test Method FTM 1, peel adhesion at 180 degrees, for the peel test angle, speed, sample width and reporting units.