The Process..

PANCRO's patented, high-vacuum process relates to the field of physics in the area of optics, which deals with the nature of light and image. PANCRO's investigations into this area have resulted in a scientific process and superior ND, which have been adapted to the field of cinematography and television.

In two hours , the "single-piece" optical-select glass is transformed into a neutral-density filter by PANCRO's own patented high-vacuum process.

Glass is cut to size, clipped to a metal tray, and hung in a large, steel vacuum system by skilled technicians.

Air in the vacuum chamber is roughed out with large mechanical pumps. Hot, high speed diffusion pumps are standing by.

Through a series of valves, diffusion pumps are thrust open, synchronizing with mechanical pumps to achieve a high-vacuum similar to atmospheric pressure on the moon.

High voltage is introduced into the chamber, out gassing the high vacuum by ionization identical to lightening in our earth's atmosphere. This electrical discharge breaks up gaseous molecules, removing them from the surface of the glass. This prepares the surface for good adhesion during the coating cycle.

When the high vacuum is achieved, a special metallic alloy is quickly evaporated at rapid speed, condensing tenaciously onto the surface of the glass in a specified uniform density of .3, .6, .9 or 1.2. and 1.5.

When the chamber door is opened and the tray removed, the glass emerges as a PANCRO ND -- an ND that is not only superior in neutrality but durable and tough.