Seismic amplitudes can provide information about rock properties if the amplitudes can be properly processed Backus (1983); Castagna and Backus (1993). This is very difficult to do given the nonlinearity of the Zoeppritz equation. The linearized Bortfeld approximation Bortfeld (1961) allows us to invert the data to obtain the reflectivities of events. Unfortunately, most forms of the Bortfeld approximation involve the primary and shear wave interval velocities which are difficult to obtain without knowing the rock properties. This paper will first look at the basic form of the Bortfeld approximation then explain a new form that eliminates the need for the interval velocities. Finally, the new form will be used on a simple synthetic.