Use of Xenon Flashtubes as a Light Source in Color and Black-and-White Scene Testers

The Cinex Exposure Tester has been widely used for many years to make timing tests from black-and-white negatives. By replacing the incandescent lamp normally found in this tester with a xenon flashtube and its capacitor-discharge power supply, the resulting stable and reproducible light output has allowed the development of a superior testing machine. The exposure gate has been modified to contain a series of neutral density steps matched to the printing machine lights; for subtractive color testing, a selected range of color filters is added to the neutral densities. The resulting intensity-scale tests closely match printing machine exposure times, thereby resolving film reciprocity differences normally present in Cinex tests. — These modified units have been used for several years in black-and-white testing with 30-w-sec input to the xenon lamp. By increasing this input to 300 w-sec, the adaptation of the tester to color-scene testing was accomplished.