Exposure conditions studied included direct film-source contact as well as the use of Mylar energy degraders ranging in thickness from 6.35 um (.00025") to 25.6 um, Studies of etching technique included variation of the time and temperature of etch, agitation of the NaOH bath, and methods of rinsing the etched film. Procedures were deliberately kept as simple as possible, and the etch bath for most of the work consisted of a beaker of NaOH solution inside a stirred water jacket on a hot plate, with temperature monitored every 15-20 minutes. Etch temperatures reported are a linear average over a smoothly interpolated plot of temperature versus time for each etch. For measuring and mapping track density, a variety of methods were tried. Microscopic observation using transmitted light, both with and without a green filter, was used at magnifications ranging from 70x to 400x. For area determinations, both the field of the microscope and transparent gridded mounting slides were employed. Films were also scanned on a Quantimet image analysis system, consisting of an automated stage microscope, a video system, and an image analyzing computer. This instrument automatically measures hole sizes and locations as well as counting total tracks. RESULTS 1. General exposure techniques: The film may be cut to desired shapes or sizes and mounted on slides or other holders. Drafting tape is useful for noncritical mounting, as it comes away clearly and does not leave a residue which might poison the etch bath. Code numbers and area boundaries (e.g., sample, standard, blank) may be scribed directly into the emulsion with a scalpel point. Parafilim is convenient for shielding portions of the film while other areas are exposed. 2. Etching techniques: It was found, in agreement with Costa-Ribeiro and Labao (1975), that if the NaOH bath was not stirred (in accordance with Kodak recommendations), an excessively rapid and uneven etch resulted. After an initial trial series, the etch bath was mechanically stirred for all samples. It was also found that the bulk-etched surface material did not uniformly rinse off the film when it was dipped in or sprayed with distilled water at the end of the etching process. In order to eliminate the mottled appearance caused by incomplete clearing of the etched surface, film pieces were placed in an ultrasonic cleaner for approximately three minutes. This resulted in a very uniform rinse. 3. Film reading: The Kodak-recommended procedure of enlarging the etched film 7x and counting the black points (hole images) with a magnifying glass is useful in producing a large, visible map for 595