Sign & Digital Graphics

December '19

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20 • December 2019 • S I G N & D I G I T A L G R A P H I C S ARCHITECTURAL AND ENVIRONMENTAL dots and images through several passes. The dots and images can be any color in the printing color spectrum. "3D printing, in the end, will be the fastest and highest quality," Kelly says, pointing out the meth- od's accuracy in imaging and its ability to achieve a greater level of detail. "There's no excess. You're only printing what you need." Another option for ADA signage is water or chemical etching, a more expensive and also more involved method that starts with raw photopoly- mer sheets made out of light-activated resin. A film negative that has been printed with Braille images is placed on top of the photopolymer sheets, which are exposed to ultraviolet light to harden the material and make it water- and chemical-resistant before placing the sheets in a water or chemical bath. Another material option is using zinc, magnesium or another metal that is exposed to the light source and then placed in the bath. "What you're doing is you're making whatever letters or graphics harder, so it won't wash away after you put it into a wash," Anderson says. "The wash washes away what you don't want." The sheets are placed in the bath where brushes are used to rub away the excess material to leave behind the Braille dots and raised images, so that they are part of a complete piece of material. The photopolymer that isn't exposed is what washes away and the remainder is dried one last time through post-exposure in a polymer processing unit to harden it further. "Photopolymer offers the ability to produce raised-image signs with very small, detailed images that you cannot get with either of the other pro- cesses," Kirk says. "Raised-image, small-detail maps are produced using the photopolymer process." The Braille dots and raised images then can be tipped through a screening process to make them a separate color from the sign substrate. They also can be hot stamped using heat and pressure to make the color adhere. Etching, however, ends up producing wastewa- ter after the photopolymer material is washed away, Anderson says. "Photopolymer takes the longest amount of time because of all the steps involved and the finishing that has to be done," Kelly says. Sandblasting and Thermoforming Sandblasting, or sandcarving, is an additional way to produce an ADA-compliant sign using a high amount of pressure and a spray of sand to remove The frosted white sign for room 1734 for a manufacturing area is leftover from a project ADA Central Signs did for a trade school on the East Coast. The sign is 0.25 inches thick with charcoal gray lettering. Image courtesy of ADA Central Signs. A photopolymer 1/8-inch thick, surface-painted ADA-compliant sign that is lami- nated to an accent backer for Room 2214. Image courtesy of Bell Company. Appliqué/raster ADA-compliant signs for Room 818. Image courtesy of Bell Company.

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