Rosco 3408

Overview

Rosco #3408 is a color correction filter (light filter/gel) from the manufacturer Rosco, part of the Cinegel or Roscolux series. The designation is Roscosun 1/2 CTO, where CTO stands for "Color Temperature Orange." It is an amber-colored filter that lowers the color temperature of a light source – it makes cool, daylight-balanced light warmer. The abbreviation "1/2" indicates the strength of the correction: it is between the full CTO (#3407) and the weaker 1/4 CTO (#3409).

Unlike pure effect or diffusion material, the 1/2 CTO is a defined conversion filter for mixing light sources of different color temperatures on set.

Technical Data

Manufacturer specifications for Roscosun #3408 (1/2 CTO):

The filter is available as sheets (e.g., 20" x 24") and rolls (e.g., 24" x 25' and 48" x 25'). It is manufactured on a heat-resistant base material; exact heat resistance and Mired values should be checked directly with the manufacturer for safety-critical applications.

Set Usage

The 1/2 CTO is used to warm up daylight-balanced sources (HMI, daylight LED, window/sunlight) and match them to warmer environments. Typical applications:

• Partial warming of HMI or daylight fixtures when full tungsten conversion is not desired.
• Matching a daylight source to existing artificial light or a warmer ambient mood.
• Subtle warming of window or background light for a more natural mix of multiple sources.

The half strength is chosen when the full CTO would be too strong (too orange), but an uncorrected source would remain too cool. The filter is stretched in front of the fixture or mounted in frames/gel frames.