Controlled Laboratory Printing Techniques.

Laboratory study of the printing process requires careful control and measurement of such vital variables as printing pressure, speed, and ink film thickness. The techniques for handling these variables are reviewed, and a practical combination for controlled work on a proof press is selected. Static printing pressure is measured with a flexing bridge such as the Huck pressure sensitive base. Correlation of the static pressure with dynamic pressure has been made using strain gages and the Brush Strain Analyzer. Speed is handled by measuring the time of passage of the cylinder over the plate with an electric stopclock. The method selected for film thickness measurement is direct weighing of the ink on the plate after establishment that resting of the particular ink does not affect results. Use of these techniques in a constant temperature and humidity room has produced highly reproducible results.