Modern laminated glass is produced by bonding two or more layers of ordinary annealed glass (or tempered glass) together with a plastic interlayer, usually polyvinyl butyral, Thermoplastic Polyurethane (TPU) or ethylene-vinyl acetate (EVA). The plastic interlayer is sandwiched by the glass, which is either passed through a series of rollers, or vacuum bagging systems, and ovens, or autoclaves, to expel any air pockets. Then it is heated to form the initial melting. These constructions are then heated under pressure in an autoclave or oven, to achieve the final bounded product (fully crosslinked in the case of the thermoset EVA). The tint at the top of some car windshields is in the PVB. Also, colored PET films can be combined with the thermoset EVA material, during the laminating process, in order to obtain a colored glass. Digital printing is now available for architectural applications by either printing directly to the glass and then laminating or printing directly to the PVB as is the case with the trademarked Dupont SentryGlas Expressions process. Full CMYK images can be printed to the interlayer prior to the autoclave process and present vivid translucent representations. This process has become popular in architectural, Interior design and signage industries for a number of years.