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The prominence of screen printed glass has changed dramatically over the 18 years since I last published an update on the very topic. Today's architectural culture calls for competitive designs, and unique, futuristic-looking buildings, particularly career centerpieces with stunning and breathtaking features. As such, architects are clamoring to incorporate decorative screen printed exterior glass everywhere, to buttress their prestigious offerings for the entire world to behold and admire. This is not surprising, considering decorative glass isn't only aesthetically pleasing, but helps to eliminate construction cost overruns because it is considerably less expensive than traditional building materials, and is quicker to complete structurally. Hence is why the Freedom Tower under construction at ground zero can break out a new floor each week.

The sheer beauty and increasing aesthetic appeal of printed glass no longer stops at building exteriors. It has found its way into numerous interior applications, too, a unique answer in forward-looking design concepts, oftentimes in higher quantity demand than its exterior cousin enjoys. As architects observe the transformation of their designs into opulent printed glass creations, many interior designers' traditional finishing treatments are fast becoming endangered species, as eye-catching, decorative glass spectacularly empowers the pleasing and distinctive effects it carries in almost any surrounding ambiance. Decorative glass, in one form or another, is a clear win-win for all parties involved.

The architectural glass marketplace is essentially fragmented into three distinct groups:

• Building exteriors: Decorative printed patterns, designs or custom images, usually for lower floors, near street level, and for construction curtain walls - known also as "spandrel," to conceal construction components, such as floor structures, columns, plumbing, wiring, elevator shafts and other unsightly, but necessary, features.
• Building interiors: Curtain walls (to conceal unsightly interior features), partitions, doors, skylights, ceiling canopies, elevators, balustrades, balconies, stair treads, floor tiles, etc.
• Furnishings: Table/counter/vanity tops, shower/bath enclosures, shelving, mirrors, etc.

As for screen printing, it was once said plain glass is just too plain - while printed glass seems to be the universal solution! For instance, modern airports anywhere in the world are earth-shatteringly expensive to build. They are, without doubt, constructed almost entirely of glass, with many screen printed pieces making up portions of the exterior, and the interiors in some significant manner.

Look carefully next time, and you will surely see patterns (lines or rows of dots in varying widths and sizes) designed to reduce sunlight's harshness without blocking vision on the other side. It also helps to provide the perpetually chaotic place with an air of openness and grandeur in presence - even when crowded with people. More recently, glass receiving the added print treatment has skyrocketed to such an extent that some airports have altered their structures to feature more than 50 percent printed glass a trend sure to continue to grow as architects realize the tremendous value provided for their creations.

Keeping it Sustainable & Safe
Architects are openly embracing decorative screen printed glass, and its acceptance in the construction business is elevated, because screen printing eradicates the obnoxiously dangerous and extremely hazardous use of acid and chemicals or the equally troublesome sandblasting process.

The screen printing technique creates a milky white, semi-transparent coating (ultra-thin/low-solid content enamel ink), actualizing the much admired "acid-etched look."

The degree of transparency can be adjusted, and can also be used for traditional line/dot patterns to yield a subtle finish. However, the way to gain even greater distinction is to print images, such as corporate logos or signage (brand names in restaurants/wine bars), or to print solid areas of a glass panel, as a whole or in part.

When used to print a partial solid on floor-to-ceiling partitions at airports - ranging one to seven feet above the ground, on a large glass panel that stands 12 feet high or more - they shrewdly conceal security/unauthorized areas, or create a separation to assist in the directional flow of passengers. Keeping the airport bright, spacious and friendly would not be possible without printed glass that can typically be eight feet wide by 12 feet or more during the printing process.

As one can imagine, printing such sizes, especially when weight can exceed a half-ton, is not exactly for the fainthearted. Since a job may typically call for 120 glass panels in four different sizes, and perhaps two or more varying shapes, the panels must be prepared beforehand (cut to size, grounded and washed), which means there are no pieces with which to play around. The ink coating has to be removed in the case of any rejected prints, and glass must be sent through the washing process again before it can be reprinted. Despite the difficulties generally not encountered by commercial graphic printers, screen printing glass easily beats the old and very dangerous alternative processes.

Ink & Coating Choices
The choice of inks available today for aesthetics and permanency has significantly helped bolster this market segment. Bear in mind, certain performance aspects of structural glass for construction purposes are controlled by strict regulations. Most glass panels that come into contact with the human body - (e.g., glass/shower doors, patio tables, office/hotel/train/bus windows) - are tempered (hardened through a tempering furnace) for safety reasons. Due to this, ceramic frit (known as enamel) is used for printing. This enamel is essentially crushed glass, so it melts into the surface of the panel upon tempering, to form a permanent coating.

Tempering glass that does not need to be toughened is a very expensive and wasteful process, which could not ordinarily compete with its un-toughened variety. Enamel is useless until it has been fired into the glass, and another medium has to be used to provide permanency for glass that has not been toughened, most popularly a silicone-based elastomeric coating. This type of coating provides a greater color gamut, including metallic that, unlike ceramic frit (enamel), can be touched-up with a paintbrush.

Without relying on radical or exotic technology, hazardous chemicals, or outdated, dangerous processes, adopting the screening process to print/coat architectural glass is a time-trusted technique. The amazing results in today's ever-challenging and demanding marketplace has stoked innovation in the minds of architects, and led to imposing creations. Nothing else seems to provide the most exceedingly and aesthetically striking buildings seen anywhere - thereby ensuring an on-going lucrative avenue for screen printing onto glass for many years to come.

Mike Young has been a specialist in high-definition graphic and industrial screen printing for more than 35 years. He is an SGIA Fellow, a member of the Academy of Screen Printing Technology and a recipient of the prestigious Swormstedt Award for technical writing. He is a consultant for the Connecticut-based Imagetek Consulting International, and specializes in troubleshooting and advancing training for high-end printing operations.

This article appeared in the SGIA Journal, May/June 2012 Issue and is reprinted with permission. Copyright 2012 Specialty Graphic Imaging Association (www.sgia.org). All Rights Reserved.