Because the fiber optic bundle is in complete contact with the Polaroid film, the image is transferred with absolute sharpness and fidelity. There is no light loss and no color shift. The Proback II lets you make two independent contact size images on each sheet of Polaroid film simply by pulling the white film tab to a predetermined position before taking the second picture. The light seal mechanism is composed of stainless steel and beryllium copper. All other interface components are black anodized aluminum and stainless steel.
Every little bit helps.