P recording heads are arranged a recording unit. Furthermore, a specific x-ray device for implementing the method comprising an x-ray emitter, an x-ray detector and a control unit is specified to control the x-ray emitter. The second arm includes a second enlarged portion, formed in its tip end portion, with a lower surface positioned lower than a lower surface of the base end portion of the second arm. In another broad respect, this invention is a process for removing paint, comprising: applying a composition containing dialkyl carbonate, hydrogen peroxide, and water to a painted surface for a time and under conditions effective to cause blistering or bubbling of the paint. Methods for measuring these spectra using the various aspects of the apparatus of the present invention are also provided.