A holey carbon film is shadowed with gold and graphitized carbon particles are deposited on a 3.05 mm grid. These particles viewed over the holes may be used for assessment of factors limiting the microscope performance. The evaporated gold forms small polycrystalline islands and within these islands lattice fringes can be resolved. Also use this specimen for the measurement of contamination rates in the EM by noting the deposition rate of carbon within the holes found in the gold film.