Green diffusion fabric used for magenta correction — neutralizes green cast from fluorescent tubes and low-quality LED fixtures.
Technical Details
Green nets are manufactured in four standard densities: Quarter Green (0.25), Half Green (0.5), Full Green (1.0), and Double Green (2.0). The fabric is made of heat-resistant polyester with a maximum operating temperature of 150°C. Spectral transmission in the 580-700nm (green-red) range is between 65-85%, while the magenta range (500-580nm) is reduced to 15-35%. Standard sizes range from 30x30cm for small units to 6x6m for large-scale installations.
History & Development
Lee Filters developed the first color-correcting diffusion nets for the television industry in 1976, as the transition from artificial light to daylight studios began. The green net emerged as a cost-effective alternative to expensive HMI lights. Rosco introduced competing products with the Cinegel series in 1983. From the 1990s onwards, today's industry standards were established due to the growing importance of color temperature consistency in digital film production.
Practical Use in Film
Cinematographer Roger Deakins extensively used green nets on "Blade Runner 2049" (2017) to match tungsten lights to daylight-based LED arrays. For exterior shots, green nets are often mounted in front of 2K/5K Fresnel lights to match artificial light to the existing daylight. The workflow requires precise light measurement: a colorimeter first determines the Kelvin difference, then the corresponding net density is chosen. Disadvantage: The light reduction requires stronger base lighting, increasing power consumption and heat generation.
Comparison & Alternatives
Green nets differ from CTB (Color Temperature Blue) filters by providing simultaneous diffusion and lower light loss. CTO (Color Temperature Orange) filters produce the opposite effect. Modern LED panels with variable color temperature (Bi-Color LEDs) are increasingly replacing net technology, as they can be continuously adjusted from 2700K to 6500K. However, green nets remain standard for large tungsten installations where LED power is still insufficient.