Welcome to our glossary that covers terms found in the printing industry. If there is a term missing that you would like added, please comment below.
Acrylic-adhesive-backed labels offer a better working temperature range and good resistance to UV light compared to other adhesive alternatives. Acrylic adhesives have excellent long-term adhesion and are suited for most sticker & label applications. Most general label films will use an acrylic, pressure-sensitive adhesive.
Backing paper is a popular name for the release-liner that's on the back of a self-adhesive sticker. You remove this layer before applying your sticker or label. It is usually silicone-coated paper but can also be a transparent PET film. The other name that we can use for backing papers is release liner.
Banding is consistent, parallel stripes in a printed image. It's caused by the print head moving across the media and the feed being incorrectly calibrated, so it moved too much or too little. The results are lines throughout your print where it should be a solid color. See this image for how this problem can look.
A bitmap image is made from millions of tiny dots called pixels. Popular bitmap file formats are JPEG and PNG and are typically used for photographs. Bitmap images will get blurry if you scale them up too much, unlike vector artwork. You can scale low-resolution bitmap artwork - learn how to do it here.
Polypropylene (BOPP) is a film with high tear resistance & rigidity. This material is ideal for beverages & many other label applications, which is why it's the industry standard for labels.
Calendared vinyl is a plastic film made from PVC. Calendaring is a manufacturing process and tells us how that PVC gets made.
Ingredients get mixed and kneaded in an extruder. The mix then passes over huge heated rollers to form a long, thin sheet of vinyl.
Calendered vinyl ranges from economy to high-grade but is best for applying to flat surfaces.
Cast vinyl refers to a plastic film made from PVC. Producing cast vinyl involves an expensive manufacturing process and, therefore, is a premium product.
Car wrapping is a popular use of cast vinyl because these materials are very stable and thin, making them highly conformable.
CMYK stands for; Cyan, Yellow, Magenta, Black (key). These 4 are process colors used to make thousands of other colors. New print technologies have added; Orange, Violet & Green to widen the color gamut, allowing you to print more colors than before. Read more about CMYK colors here.
Delamination happens when the transparent, protective film that’s been applied over the printed layer starts to come away.
Delamination can happen because of excessive abrasion or that the adhesive isn’t strong enough to hold the clear laminate in place, especially if the label is stuck onto curved surfaces.
The term ‘die-cut’ originates from an old method using pre-made metal ‘dies’. Strips of sharp metal are formed into the wanted shape to make a cutting ‘die’.
Die-cutting today means the sticker or label is cut around the shape of your artwork in a custom shape, through both the vinyl and backing paper layers. They can be any shape and are popular stickers.
The words fluorescent, neon, and Day-Glo can all be used interchangeably to describe a color that looks very bright. Fluorescent colors are usually limited to only a few shades because the original pigments are only available in yellow, red, orange, green & pink. Fluorescent colors absorb non-visible light and convert it into visible light, which is why they look so bright. Read more about fluorescent colors here.
Stands for grams per square meter (g/m2) - unit of measuring mass per area.
Often understanding the thickness is hard because you need to know the density. Popular backing papers for stickers range from 80-150 GSM whereas labels on rolls typically have a much thinner backing paper, less than 60 GSM.
Hot melt (adhesive)
Hot melt is a type of adhesive that contains 100% solids, unlike water-based or solvent-based adhesives. It is a Thermoplastic adhesive so becomes mouldable when heated up. Hot melt adhesive is most commonly used in glue guns. It’s sometimes applied to the back of printable media for hard-to-stick to surfaces, such as tire stickers or oil drums & cardboard box sealing as it has high tack, low-shear properties.
Inkjet printing recreates a digital image by spraying tiny droplets of ink onto a substrate. Inkjet printers combine cyan, yellow, magenta & black inks to create high-resolution images. Some inkjet printers print white, orange, green, and violet to increase the number of colors they can print, known as the color gamut.
Kiss cutting refers to how a sticker or label is cut. Kiss cut stickers get cut through the vinyl layer around the edge of your sticker, without cutting through the release liner.
Only cutting through the vinyl layer leaves an extra backing around your sticker which makes it easier to peel & apply.
A label is the same as a sticker, just on sheets or rolls. The terms can be used interchangeably for a self-adhesive piece of printed plastic or paper. Labels are typically used on mass-produced products such as beverage bottles.
A laminate is a layer covering the printed image of a sticker or label. Laminates are used for protection or aesthetics. Laminates generally come in 4 finishes; gloss, satin or matte, or soft-touch (similar to matte). A laminate can be a layer of clear plastic, but it can also be a liquid coating that's applied. Liquid laminates are not as durable as applying a plastic layer but are typically more eco-friendly.
There are many ways to cut stickers & laser cutting is one. CO2 lasers, about 190 microns thick can either die-cut or kiss-cut vinyl and other media to any shape required.
Laser cutters can run at over 100 linear meters per minute and have a cutting accuracy of +/- 0.1mm.
Latex ink printers use water-based inks where the latex acts as a carrier for the color pigments. Heaters within the printer dry the latex as it comes off the printer so the ink cures instantly, leaving no time before the media can be finished (laminated & cut). The final printed product is durable and eco-friendly because of the water-based inks used.
A metalized film is a polymer film, usually PET, that's coated with a thin layer of metal, normally aluminum. They give the film an extremely shiny, near chrome, metallic appearance. They are usually quite stiff because they need a hard polymer film to get a very shiny finish. Metallised films are used to make mirror silver, mirror gold, holographic, and other shiny stickers.
A metric unit of measuring length also called Micrometre, is equal to one-millionth of a meter, 0.001mm, or about 0.000039 inches. Its symbol is μm.
Print media (aka. vinyl) are typically between 50-80microns in thickness (0.05mm to 0.08mm). This doesn’t sound very thick, but it’s perfect for most applications.
An Imperial unit of measuring length is normally referred to as thou, a thousandth.
It’s 25.4 μm (micron) or 0.001 in. Its symbol is thou or mil. Often used in the USA to measure the thickness of media, whereas in Europe the unit of micron is normally used.
Misregistration describes a cut machine cutting a sticker or label incorrectly by being offset in the X or Y-axis. It gives an uneven border to your sticker and can look particularly bad. It is unusual to happen with digital cutters unless they are poorly calibrated.
Monomeric vinyl is a grade of calendared PVC film. Monomeric grade films use a single polymer and are therefore cheaper to manufacture. They’re typically lower-grade PVC films, used for short-term, promotional uses.
Neon, also known as fluorescent, describes a color that is really bright. Neon pigments absorb non-visible light and convert it into visible light which is why they seem to glow.
Peel adhesion (adhesive)
Peel adhesion is defined as the force needed to “peel” an adhesive tape from any given surface. This is typically tested at 90 and 180 degrees. Results expressed as N/25mm then the surface it was tested on, usually stainless steel or glass, after a specified time, usually 24 hours.
Peel adhesion values increase over overtime for pressure-sensitive adhesives, which are the most common glues used for stickers & labels.
To read more see the article; What is a peel adhesion test?
Polyethylene film falls into two main categories; low-density (LDPE) & high-density (HDPE).
- LDPE is soft, flexible, and has good tear and moisture resistance, and it's great for grocery bags and food packaging.
- HDPE has good impact strength, puncture resistance, and chemical resistance but low gas barrier properties, making it suitable for premium labels.
Polyester (PET) is a printable film with great durability. This makes polyester great for labels & stickers with outdoor applications. PET films have good; temperature, UV, and chemical resistance.
A plasticizer is a substance that’s added to a material to make it softer and more flexible.
Plasticizers are used in PVC films to make them more flexible. This can make PVC stickers some of the easiest to apply. However, plasticizers can also cause vinyl films to shrink, so it’s important to get the right balance.
Polymeric vinyl is a grade of calendared PVC vinyl. Polymeric Grade PVC films use more than one polymer, which means they’re more expensive to manufacture than monomeric films. Polymeric calendered vinyl gets used on longer-term applications, such as window graphics or stickers.
Polyvinyl chloride (PVC) is one of the world’s most-produced polymers. There are two types of PVC; rigid & flexible.
The flexible version is used to make PVC films, often referred to as vinyl or vinyl films.
PVC is being used less & less in some industries because it’s harder to recycle than PP or PE alternatives.
A release liner is the backing to a self-adhesive sticker or label that gets peeled away before application. It is usually silicone-coated paper but can also be a clear PET film. The other name is backing paper. Silicone release liners are notoriously hard to recycle because of their silicone coating.
Reverse printing is a process where a design is printed as though mirrored, so when it's looked at through the clear media, the image looks correct. It is used if you want the adhesive of the sticker over the printed image, great for stickers to apply inside windows. We call these front-adhesive stickers.
Rotary screen printing
Rotary Screen Printing is the same concept as screen printing but in a cylinder. It’s prevalent for high-quality textile printing.
When rotary screen printing, a machine presses a paste or ink through the mesh on a cylindrical screen onto the subscribe. Each color is applied separately to achieve full-color prints.
Rotary screen printing looks like this.
A rubber-based adhesive is an alternative to an acrylic adhesive. A rubber-based adhesive has superior long-term adhesion, especially on plastic surfaces. However, it can feature a yellowish tint that isn’t good for transparent containers. It’s also better in relatively benign environments where it won’t experience extreme hot or cold temperatures or exposure to sunlight. It’s generally used on labels for high-tack applications, such as; oil drum labels and tire stickers.
When screen printing, a screen is made by stretching a mesh onto a frame. The chosen tension & mesh size determine how much ink gets transferred to a substrate.
A design is then transferred to the screen by developing an image onto it using a UV cured block. The shape of the stencil determines the pattern that’s printed on the substrate.
A rubber squeegee, either hand or machine operated, then pushes ink through the mesh onto the paper or plastic substrate. Screenprinting inks can be solvent or water-based and can be cured by UV or leaving the water/solvent to evaporate.
Shear testing (adhesive)
When adhesives are tested in shear, two pieces are bonded together and pulled apart in opposite directions.
This image helps to explain.
Adhesives for stickers & labels are tested in shear to see how they will perform in real-world applications.
All plastics will shrink over time; this includes all types of plastic stickers and labels. Shrinkage rates vary but are typically between 0.5% to 3%. This is completely normal. Really soft PVC films with lots of plasticizers are some of the types of vinyl that will shrink the most. See shrinkage rates of various materials.
Solvent-based adhesives may lose up to 50-70% of layer thickness during drying as the solvent evaporates. Solvent-based, pressure-sensitive adhesives are one of the most popular adhesives used today.
A sticker is a self-adhesive piece of paper or plastic, typically printed. A sticker can be on a roll or sheet, but it tends to be called a label in this case.
The term sticker & label can be used quite interchangeably, so it's best to read into more detail if you're looking at buying stickers or labels.
Surface energy’ is a relative measurement of the energy at the surface of a material. It's often quoted in units of mN/m. It's important because it defines how easy material is to stick to. To read more about different materials & their surface energy read this article.
Tack is the property of a pressure-sensitive adhesive that allows it to stick to a surface with only slight pressure.
The higher the tack, the more a sticker will adhere to a surface on the first application, making it harder to lift & re-apply.
Thermal transfer printing
A very thin layer of ink, less than 10 microns thick, is applied to a PET carrier and made into rolls, known as a thermal transfer ribbon (TTR). The ink is typically made from a wax & resin mix.
A thermal print head applies heat and pressure to the ribbon to melt the ink, so an image gets printed to the media. Each spot or process color is applied separately to make full-color prints.
Thru-cut in the label market refers to how a sticker is cut. It tells us a sticker or label is cut through both the sticker & its backing paper, meaning they’ll arrive as individual pieces, not on sheets or rolls.
A UV inkjet refers to traditional inkjet printing, but where the ink cures by exposure to UV light as an alternative to solvent or water-based inks that take time to dry. UV curing can make printing much faster and eco-friendly because potentially harmful solvents don’t get released into the environment.
Variable data printing
Variable data printing refers to when each sticker or label in the same batch has a unique piece of data printed. Popular reasons for variable data printing are; QR codes, barcodes, dates, numbers or SKUs - typically something that helps to identify a product. If you'd like custom stickers or labels with variable data, you need to provide a CSV with the data & let us know which piece of data needs to change for each label.
Vector artwork is made from geometrical formulas (aka maths) to represent images. You can create vector artwork in design programs such as CorelDRAW, Adobe Illustrator, and Inkscape. The benefit of vector artwork is that it will not go blurry when scaled like bitmap artwork will. Read more here.
Water-based adhesives are usually non-hazardous and eco-friendly, containing no VOCs. They are a popular alternative to solvent-based adhesives and are widely used for pressure-sensitive, self-adhesive films.
Wetting out (adhesive)
Wetting out of adhesive involves the surface energy of the material and the formulation of the adhesive.
When an adhesive ‘wets out’, it describes how the adhesive flows to cover a surface to maximize the contact area. Higher surface energy materials give a better wet-out and therefore a stronger bond.