Control The Light, Not The Color

Modern digital cinema cameras create images with precision unlike any other tools in the history of cinematography. The manufacturers of digital cinema cameras build in very specific color science both physically at the sensor site and in the digital conversion process to delivery. 

In the quest for accurate color rendition, various amounts of visible and infrared (IR) light near and past the visible spectrum are allowed to pass onto the sensor depending on the manufacturer specifications. This is achieved with an Optical Low Pass Filter (OLPF). Often IR light can be imaged in black level when density is added using filters because the OLPF is tuned only for light entering the lens unfiltered. IRND filters are needed that either cut or suppress the IR light before it hits the sensor to allow for only light in the visible spectrum to pass.

The chart above shows other brands of IRND passing visible light in a wavy pattern. This is artificially restricting the light and therefore color science the manufacturer intended before it hits the OLPF. IR cut filters also fail to suppress IR light past a set wavelength near the visible spectrum.

The chart also shows the Tokina Cinema PRO IRND suppressing IR light completely in a flat line well beyond the visible spectrum. This allows for the OLPF designed by the manufacturer to pass visible light in the manner intended while surpassing all IR light out to 1200nm which is well past the visible spectrum.