Fuji Prescale is a Mylar tactile pressure indicating sensor film, distributed by Sensor Products Inc.,that instantly reveals surface pressure magnitude and distribution between contacting or impacting surfaces. When placed between the surfaces, it permanently turns different shades of red, with the color intensity being directly proportional to the amount of pressure applied. Prescale pressure indicating film shows precisely how bolted joints engage and deform under stress. Pressure variations are shown by the color changes left on the film. These colors can be compared to a color calibration chart to determine the exact pressure distribution. While no instrumentation is required the film impression can also be digitalized through imaging. Topaq, an imaging analysis program, assigns colors to pressure values. The graphic pictured right reveals pressure variations in a bolted joint interface. The non-uniform pressure distribution may be caused by a variety of factors, including dimensional irregularities, surface roughness and uneven bolt torque. Since it is difficult to measure the force exerted by the bolts directly, torque values are often assigned for assembly based on trial and error. Prescale speeds assembly by quickly validating and confirming sufficient bolt torque to assure uniform interfacial pressure. To adjust torque values, the film is placed at the bolted joint interface and the bolts are tightened to apply pressure. The film is then removed and reviewed to see if the pressure is uniform. Common applications for Fuji Prescale include measuring the interface pressure of bolted joints, gaskets, clamps, fasteners, connectors, flanges, valves, o-rings and welding heads, among others.