The specimen is a semi-confluent layer of 3T3 cells in tissue culture that were fixed and stained using DAPI. Photomicrographs were recorded utilizing a UPL 40x fluorite objective coupled to a WU dichroic filter combination. The fixed and stained culture was also photographed simultaneously with phase contrast illumination to visualize non-fluorescent cell structures. A 3.3x projection photo eyepiece was used to transfer light from the intermediate image plane to the photographic emulsion.