Backlit banners need enough ink density to look good when backlit, but not so much that they look dark when frontlit.

“Try to learn something about everything and everything about something.” 

—Thomas Henry Huxley

 

For a material that’s so commonly found and widely used in our industry, banners come in a perplexing variety of materials, qualities, densities, surfaces, sizes and coatings. The best way to make some sense out of it all is to make a list with definitions, like an encyclopedia. Then you too can know something about everything (banner-wise of course), but probably not everything about something (that would be a daunting task).

 

TYPES OF BANNERS

Vinyl—The most ubiquitous type of banner, vinyl banners almost comprise an encyclopedia of its own. The main structure of vinyl banners is often a polyester grid of fine mesh known as scrim. This gives the banner strength. The heavier the mesh, the stronger the banner, but the more visible the grid pattern is on the banner surface. This grid is then coated with PVC. Banner that is made without the scrim mesh is both less expensive and less strong than scrim vinyl banner. True solvent and UV-curable inks are the best choices for uncoated vinyl banners. Vinyl banner is the best material for general, all-round use—it is tough, durable and weather resistant.

 

Mesh—This banner material is similar to the scrim vinyl banners in construction, except that the spaces between the polyester grid are left open. This serves several purposes. With outdoor applications, wind can present a lot of stress to a large, exposed banner face. The holes in mesh banner allow the wind to pass through, relieving a lot of the stress. Another benefit is for building wraps that cover windows. The holes allow light through so that the occupants of the building don’t get SADs. The third use is for specialty exhibits and theatre effects. Lighting can be used to make scenes appear and disappear behind the mesh screen. Mesh banner is also available in double-sided versions.

 

Large outdoor banners subject to high winds need to be printed onto a mesh banner to let the air through.

The main thing that differentiates various mesh banners is the strength of the mesh and the size of the holes. The larger the holes, the more light and wind can pass through. But this also means that less of the banner area is printable surface, making the images less distinct. The further the viewing distance from the banner, the less difference this makes.

 

Cotton—Cotton banner material provides a loose, natural look that is appropriate in many situations. It is only appropriate in controlled situations though, as it is not waterproof or cleanable. While many ink types will print onto cotton, dye inks work the best. A backing sheet is often required to stop the cotton from stretching in the printer.

 

Polyester—These banner fabrics are water proof and very tough. Polyesters also have a huge range of translucence. They can vary from completely opaque banners that can be imaged on both sides to almost invisible wisps of silk-like cloth that provide a ghostly ambience. Solvent inks will adhere to these materials, but often look washed out. Dye-sublimation is usually the best choice for imaging onto polyester. These bright, dynamic banners look good indoors or out.

 

Paper—What can we say about paper? Cheap, not durable, but effective for many applications. Printable with almost any inks and printers, it is an ancient workhorse that will probably always be viable.

 

Tyvek—This is a special banner cloth developed by DuPont that is made from spun polyethylene, it is tough, waterproof and inexpensive. Most types of ink can print on it, some in coated format only, of course. It can be sewn, glued, grommeted, cut, stretched or twisted.

 

Canvas—Cotton-based canvas banner material usually has a white coating on one side to facilitate printing. It creates art style prints that are attractive and durable. Best for indoor use only as the exposed cotton back doesn’t tolerate moisture very well.

 

PRINTING

With so many types of banner materials available, it naturally follows that there are different ways to print them. 

 

Aqueous inks will only print onto specially coated banner material (other than bond paper), but many kinds of banner materials are available with coatings. Since aqueous inks are not very waterproof, a clear coat is often required to seal them (unless a really short-term indoor use is all that is needed).

 

True-solvent inks, as stated above, are a great choice for most uncoated vinyl banner materials. The inks bite well into the materials, offer good color and are very scratch resistant. The downside is the inherent safety and health issues of solvent inks, which require ventilation and careful handling. 

 

Mild- and eco-solvent inks will print onto many banner substrates, but don’t bite very deeply. This necessitates a clear-coat or laminate, or printing onto specially coated substrates. Full solvent inks work well on most banner materials in their raw, uncoated state and bite deeply into the surface for an unparalleled grip.

 

UV-curable inks have a type of adhesive in their formulation that creates a bond with the substrate during printing. This bond allows UV inks to stick to almost anything. However it is not as solid an adhesion as mild solvent on coated banners or full solvent.

 

Indoor banners need to be of smoother material, but don’t need to be as tough as outdoor banners.

Dye-sublimation inks have long been a popular choice for printing onto polyester banner material. The colors remain bright and clear and can transfer right through the fabric for a double-sided print with one pass. New digital inks that have been designed especially for fabrics (and originally used in screen-printing) are available that include acid and reactive dyes as well as pigmented inks. Many of these processes require additional processing like heat curing, washing, etc.

 

FABRICATION:

Fabrication methods are similar for all banner types. Edges are usually hemmed- either by sewing, welding or adhesives. This creates an edge that won’t easily tear or fray and provides strength for the attachment method. Attachments can be poles or ropes that slide into pockets created by the hem or grommets placed into the hem area.