Fig. 6. Photo enlargement of disc.

Computer-Based Contrast Enhancement Results. The negative was digitized using a Perkin-Elmer Scanning Densitometer set to six microns diameter entrance aperture. Optical density was achieved to 16-bit resolution. The negative was scanned and digitized three times; each scan was made using a color filter having the approximate spectral distribution as the dye layers in the negative¹. System output was recorded on 1/2 inch magnetic tape at 1,600 bits per inch density for processing and display by a digital computer. The region studied was only slightly larger than that of the disc in order to conserve