In the last few years Scanning Probe Microscopy (SPM) has become one of the primary tools of science and technology. In addition to topographical imaging, surface potential, conductivity, optical, ferroelectric and magnetic properties that can be studied down to the nanometer level. However, quantitative and sometimes qualitative studies of fundamental physical phenomena in meso- and nanoscale systems are often hindered by SPM imaging artifacts. Here we briefly discuss the principles of operation and the major sources of artifacts in electrostatic measurements by SPM.One of the most well known techniques for local potential imaging is Scanning Surface Potential Microscopy (SSPM). SSPM is based on dual pass imaging. The grounded tip acquires surface topography during the first pass.