New fabrics and printing technologies open up design possibilities.
Compiled by Fabric Architecture magazine
Architectural graphics today means more than simply selecting a typeface for a building’s address, room numbers or corporate site address sign. With durable, wide-format fabrics designed for large-format digital printers available, architects have a multitude of options to choose from, including faÃ§ade and fenestration treatments to whole building wraps, the ultimate “building as sign” (à la Venturi and Scott-Brown), not to mention the relatively traditional avenue/pole banners and wayfinding signage on site. Indoor application possibilities include room dividers, ceilings, walls, and windows and skylights where mesh fabrics can serve not only to enliven a space with graphics but also help reduce solar gain. As digital printing, screen-printing, and even litho printing are made available in large-format equipment that can transfer images onto fabric, designers are utilizing fabric graphics in diverse ways to great affect. (For a description of these printing methods, see Terminology at the end of this article.)
A matter of scale: from city to building to room
The word “wayfinding” means exactly what you’d think it might mean: it’s the process people go through when they’re orienting themselves in an unfamiliar environment. Today, wayfinding is a much-discussed topic among architects and designers. It is part of their job to make sure everyone can find their way around, both inside buildings and in outdoor environments. Yes, wayfinding encompasses much more than signs, but signage is always a significant part of any installation. Fabric graphics is an economical, and increasingly significant percentage of signage for buildings and environments, although it’s fair to generalize that fabrics are used more in temporary situations than in permanent ones. These temporary cases can include construction site hoardings (for pre-construction and during construction branding opportunities), to site banners and directional signage, to faÃ§ade treatments that announce the look of future construction (as in restoration projects of historical buildings where public access it necessarily reduced, but not prevented during restoration or reconstruction. Often a full-sized image of the finished faÃ§ade is printed on a scrim that is wrapped around the building scaffolding.)
Wayfinding on a grand scale can use entire buildings. For the 2002 Salt Lake City Winter Olympics, many city towers were wrapped in mesh fabric digitally-printed with images of in-motion Olympians as an aid to help visitors find events. The branding extended to venue signage and color-coded backdrops, as well as street and site signage. “The wayfinding project begins with a thorough analysis,” says Daniel Waeger, senior designer with Infinite Scale Design Group, the brand manager for the 2002 Olympic Games. “That’s especially true with event signage, where a lot of people gather in a short period of time and crowd the space.”
The careful analysis of pathways, intersections and architectural features applies to all scales of wayfinding graphic projects. Office and commercial buildings have underground parking, street-level retail, and frequently above that offices, condos and apartments. People coming in and out need to know how to get into a garage; if they’re going shopping, or visiting someone in the condos, they need to find these in an easy-to-understand way. At sporting events, visitors to stadiums or sports facilities need to find their seats, the restrooms, the food vendors and the exits. Parks, museums, real estate developments and cities all have wayfinding needs that can, in part, be addressed with fabric graphic elements.
At the building scale, imagine the case of a hospital (or any healthcare facility) and the importance of clear wayfinding. The goal is to assist people who are under distress with signage that is very clear: a little larger, a little simpler to read and a little more frequently spaced than might ordinarily be expected. Signs made of sheer mesh fabric, large-scale typography, custom photos and column-mounted directories should be designed to complement interior spaces. However, designs must strike a delicate balance between standing out and blending in; designs must complement the specific environment but still be noticeable and effective enough so people who need to utilize it can read it and understand it correctly.
Flexible fabrics versus rigid substrates
In the not-so-distant past, designers were limited to pressure-sensitive cut vinyl or sewn appliquè methods for outdoor fabric graphics. Due to advances in digital printing technology, it is now possible to apply full-color prints to almost any substrate, and color matching is no longer an obstacle. Solid-white flexible substrates are used to print structural canopies, commercial awnings, construction fences, signs and building wraps.
It is assumed that an outdoor fabric can withstand wind, rain, cold, heat and so forth, but the fabric membrane must be manufactured and installed properly in order to meet these outdoor conditions. Heavyweight fabrics are often perceived as being more durable, when in fact it is the strength of the reinforcing fiber that dictates the strength of the end product. Because clients can be price sensitive, there is the temptation to go against the recommendations of a manufacturer or printer, when the wisest return for a job may actually be a stronger, more expensive base fabric.
According to Brian Rowinski, of Rainier Industries, expert fabric graphics fabricators, two of the biggest challenges faced in creating outdoor graphics are engineering requirements and building code restrictions. “In general, city officials require more education and advisement regarding the capabilities of outdoor fabric graphics. Usually they refer to the code books that are published by the local fire departments, but these codes were typically written prior to the advent of the new fabrics that are available,” says Rowinski. He recommends that architect and the graphic fabricator meet with officials to plead their case to prove the viability of the performance of these fabrics. Manufacturers are continually introducing stronger and more durable outdoor fabrics, as well as “green” products that will reduce the industry’s carbon footprint by being either recyclable or biodegradable.*
For designers who don’t want to take any chances, the first choice is the tried-and-true screen printing. “Screen printing may last 10 years,” says Gary Buermann, owner of G&J Awning Co., Sauk Rapids, Minn. “Digital printing may only last three to five years [because of the ink], but it is getting better.” Durability issues with inks are being addressed, and many manufacturers are improving the compatibility between inks and fabrics. However, inks aren’t the only factor in creating acceptable digitally printed awnings. To get a good dpi resolution requires a fabric with a topcoat that will absorb the ink and dry quickly. “When you put a drop of ink down you want it to maintain a certain size,” says Zola. “You don’t want it to grow. The more it grows the worse the resolution; the topcoat controls that.” New fabric topcoats have improved dpi resolution.
Here is a checklist of questions to ask yourself when considering ink and fabric for your next project:
- Interior or exterior? External installations will be affected by the elements, which can change the fastness of the colors and the structural integrity of the product. However, internal installations can also be affected by ultraviolet light through windows and skylights. Consider a protective layer between the source of light and the printed product, such as UV film on a window.
- How will the project be installed? Is this an awning or an anchored construction? Is this a flag suspended by one edge, or a banner anchored on all corners?
- Will the piece be sheltered or exposed to the sun?
- What is the orientation of the installation? Sunlight from the south and west will affect color fastness more than from the north and east.
- Will the project be in place during the summer or winter? In Seattle or Scottsdale? High, direct sunlight will have a strong effect on color.
Unless you have chosen a special product with color fastness built into the fabric, and a graphic process like appliquè, most outdoor projects have a fairly short life, a life measured in seasons or a year or two, not decades.
Different types of inks have different issues of “fastness,” such as fastness to light, heat, ozone, pressure or rubbing. Transfer or dye sublimation inks on polyester generally have lower light fastness than selected acid dyes on nylon. The ink or dye combination that would have the longest light fastness would be direct print inks developed for use on special nylon fabrics designed for flags. These inks are set with steam.
Inks applied on the surface of the fabric such as ultraviolet- or infrared-cured inks are fused to the fabric. The heat or light turns the ink into a polymer and fuses it to the fibers. Improper curing causes images to scratch, crease or abrade. UV works best on polyester fabrics in indoor applications. For digital solvent and UV printing, the best results are achieved on fabrics that have a top coating, generally acrylic, urethane or a combination. The coating gives the ink something to adhere to so it doesn’t penetrate the fibers before it is completely cured.
Fiber content should be considered when choosing fabric for external use. Cottons are not generally used outdoors. Polyester, nylon and acrylic are better choices. Acrylics are more UV-resistant and retain their strength better than polyester, with or without printing.
Selection of fabric that will be UV-resistant will not mean that the ink is more or less lightfast, but that the underlying substrate itself will be less affected by light. Fabric treated with UV absorbers will respond to UV light differently than natural fibers. It may not be logical that a natural fabric would respond to light more poorly than a dyed fabric; however, a dyed fabric may have been manufactured with a dye containing a UV absorber.
A UV-protective top coating — either as a liquid or laminate — on top of the image will give the entire project longer life. Coatings may change the “hand” (feel) of the fabric and make a soft fabric stiff.
The weave of the fabric may affect light fastness and fabric strength. A tighter weave or a smoother fabric may have less fading than a coarser weave fabric. The coarser weave will present more surface area to the sun.
While “results may vary,” your project will have a life expectancy that ranges from short to a substantial length of time. It is possible, using a complex formula develop by the American Association of Textile Chemists and Colorists (AATCC) to calculate project life expectancy using detailed variables that include latitude, angle and intensity of the sun, amount and density of cloud cover and elevation, among others.
The general rule is, expect the shortest life outdoors from dye sublimation on polyester. Direct solvent printing on an uncoated fabric, on a coated fabric, and on a coated fabric with a protective top-coat treatment will each give a relatively longer life, in that order. For something that will need to last years or decades, consider appliquè on a UV-resistant fabric.
Graphic file prep
- Use vector based software (it has the ability to handle typography as well as images.)
- Create files to a common scale. This makes it easier to work with and save, and makes the printer’s job easier.
- Use high quality, high-resolution images.
- If using vector art, the size of the print does not matter as the art can be infinitely scaled.
- Convert type to outlines to alleviate any problems with font conversion.
*The Industrial Fabrics Association International (IFAI), publisher of this magazine, annually publishes a Sustainability Portfolio (the March/April issue of Fabric Architecture) which lists numerous fabrics and their manufacturers, and specification charts of these fabrics, as well as fabricators of awnings, canopies and fabric structures. Many of these fabrics are listed as recyclable.
How big do you want to print? 64 in. or less is most common; Over 100 in. is called grand format printing. The maximum width of digital printing to date is 196 in. (16.4 ft. or 5m).
Appliquè: Letters and forms are cut from fabric and sewn on to the base fabric. When the letters are cut out of the fabric and replaced by different-colored fabric, they are called “cut-out letters.”
Dye sublimation: The basic inkjet dye sublimation process uses a heat sensitive sublimation dye, dissolved in a liquid, to print graphics and text onto special inkjet paper. This is called a dye sub transfer. The dye sub transfer and a sublimatable item are then placed into a heat press. Then the heating cycle is completed, the image on the paper has been transferred to the fabric and has actually become a part of the surface.
Heat Transfer: Images are baked into fabric using a large vacuum. It is very exact, creating bold color separation. However, it doesn’t blend colors well.
Ink-jet printing: Produces photographic quality images on nearly any material using a computer scanner. The images are rich and detailed, but the inks have a limited outdoor life span unless top-coated.
Litho printing: (also known as lithography, lithographic printing or offset printing) works on the basic principle that oil and water do not mix. An image is affixed to a prepared surface of a flat stone, water is floated on the surface but is repelled where the image occurs; ink is spread on top of this and adheres only to the greasy image areas and is transferred to the fabric. Commercially, litho printing stones have been replaced by flexible metal plates. Used primarily for indoor applications.
Silkscreening/screen-printing: A process that transfers graphics onto another material using special screens. Ink is spread over the top of the screen and printed on the fabric face.
Solvent-based printing: Very simply, inkjet printing using solvent-based inks, similar to screen printing inks but the inks are formulated for digital printing.