The 9" Matthews Wire Half Double Diffusion is impervious to rust and holds up well under uneven, intense heat, thus making it preferable for use with open face or Fresnel lighting fixtures. Stainless scrims do not diffuse the light; their function is to reduce light output at the source. Scrims do not affect the color temperature and produce no electronic interference. Scrims are available in single, double, half single, and half double configurations. Halves are employed to reduce a portion of the beam and are commonly used when the light is striking the plane of the subject or background at an angle. The half reduces the light falling on the nearest part of the plane to balance with the light reaching the most distant part of the plane.
The outer edges are color-keyed for rapid identification: green is a Single, green with silver is a Half Single, Red is a Double, and Red with Silver is a Half Double.