Experimental verification of three phase shifting mask patterns designed to characterize projection printing tool illumination and phase shifting mask performance is presented. Both patterns printed in photoresist and AIMS aerial images of a four-phase reticle appear to validate scientific principles. Experimental results are compared to simulation for all three monitors, initial analysis is offered, and ideas for future work are discussed. It is concluded that impressive mask making suggests the usefulness of the phase shifting mask as a precision instrument for characterizing optical lithography. The linear phase grating (LPG), a four-phase chromeless pattern designed to monitor the illumination in a particular quadrant of the pupil, behaves as expected when the smallest features are roughly larger than a wavelength. The linear phase ring (LPR), designed to monitor light in a particular circular region within the pupil, agrees well with simulation although signal strength is low. Future redesigns promise a maximum signal of 22% of the clear field intensity for monitoring quadrupoles. The third pattern, the interferometric probe monitor for phase shifting mask performance (IPM-PSM), measures the phase and transmission imbalance between shifted regions of an alternating phase shifting mask. Although potentially limited by low signal strength, the IPM-PSM behaves generally as expected.