Rosco 103

Overview

Rosco 103 refers to the diffusion filter Roscolux #103 "Tough Frost" from the manufacturer Rosco within the North American Roscolux system. It is not a lamp, an ANSI code, or grip hardware, but a colorless to slightly warm diffusion filter (gel) that is stretched in front of a light fixture or inserted into a filter frame to soften hard light.

Rosco describes the material with the properties "wide diffusion and warm center" – meaning broad light diffusion combined with a slightly warmer center of the light beam. This places #103 in the "Frost" family of Roscolux diffusions, which has a stronger diffusion effect than the lighter "Hamburg" or Opal types.

Construction and Material Properties

The "Tough" designation refers to Rosco's heat-resistant filters for hot lights (Tungsten/Halogen). Rosco manufactures these filters in a multi-layer construction where the effective layer is sealed between protective clear film layers. This is intended to prevent color or dye migration and to keep the film dimensionally stable even under continuous heat exposure.

• Product Line: Roscolux (Tough series for Hot Lights)
• Type: Diffusion filter / Diffusion gel (not a color effect filter)
• Effect: wide diffusion, slightly warm center
• Application: directly on the light fixture, in filter frames or barndoors

On-Set Use

On set, Roscolux #103 is used to break the hard edge of a direct light beam, soften shadows, and make skin tones appear more flattering. The stronger diffusion increases the effective light source, reducing contrast and shadow hardness. The slightly warm center makes the filter popular for portrait and interview lighting.

The filter is available from specialty dealers as sheets (typically 20"×24") and as rolls (e.g., 24" width). It can be cut to size and attached with clothespins (C47), gaffer tape, or in frames in front of the fixture.

Distinction / Risk of Confusion

In the European filter numbering system (Lee/Rosco E-Colour+), the number 103, however, denotes a color filter: E-Colour+ 103 "Straw", a warm, straw-colored conversion filter for slightly warming the light. Therefore, "Rosco 103" can mean two different products depending on the system – in the Roscolux system, the diffusion "Tough Frost," and in the E-Colour+ system, the color "Straw." When ordering, it should therefore always be specified whether Roscolux or E-Colour+ is meant.