Popular throughout the second half of the twentieth century for both machine tools and architecture, anodized metal can also be used to transpose photographs onto its surface. For over 50 years, the technique has been one of the principal methods by which labels and barcodes are exported onto metal surfaces. Unlike laser engraving, which many mistakenly believe to be a more indelible technique, photo anodizing never breaks up the metal’s outward layer; instead, photo negatives are printed on polyester film and then exposed onto the photo-sensitive metal.
aluminum bar code labels
On December 21, 2007, the U.S. Department of Transportation published a final rule explaining the Federal Highway Administrations (FHWA) requirements for maintaining traffic sign retroreflectivity. According to these requirements, which can be found in the Manual of Uniform Traffic Control Devices (MUTCD), all municipalities must maintain a minimum level of retroreflectivity for all traffic signs and pavement markings which are open to public travel.