Lee #250 'Half White Diffusion'—medium diffusion filter with 55% transmission. Pronounced light scattering with 'wrap-around' effect while maintaining shadow detail—most versatile for professional film lighting.
Technical Specifications
Lee #250 "Half White Diffusion" (also called "1/2 White") is a medium diffusion filter made of milky white polyester with 55% light transmission (0.85 stops loss). The filter spreads light at an angle of 35-45°, producing significantly more "wrap-around" than 216, but less than 251. The material thickness is 0.13mm, with heat resistance up to 120°C. The name "Half White" refers to its intermediate position between 216 (Light) and 251 (Heavy) in the Lee diffusion series.
The "Book Light" Standard
250 Diffusion is the classic choice for "Book Light" setups: a Fresnel spotlight shines onto a white reflective surface (bounce board), which throws the light through a 250 frame in front of the subject. This two-stage diffusion (bounce + diffusion) creates extremely soft yet controlled light with natural falloff. Cinematographers like Roger Deakins use this technique for intimate dialogue scenes where the light should support the emotion without being noticeable.
Comparison with Other Diffusers
| Parameter | 216 (Light) | 250 (Half) | 251 (Quarter) | 129 (Heavy Frost) |
|---|---|---|---|---|
| Transmission | 82% | 55% | 40% | 30% |
| Light Loss | 0.3 Stops | 0.85 Stops | 1.3 Stops | 1.7 Stops |
| Spread Angle | 15-25° | 35-45° | 60-80° | 90°+ |
| Shadows | Defined | Soft, visible | Very soft | Almost eliminated |
| Wrap-around | Minimal | Medium | Strong | Very strong |
Applications
250 is suitable for: Key light in interviews and portraits (the "TV news standard"), window light simulation with natural falloff, fill light while maintaining directional characteristics, and as frontal diffusion in beauty setups. For exterior shots, 250 in large frames (12x12, 20x20) serves as an "artificial cloud" for flattering skin tones. The balance between softness and definition makes 250 the most versatile diffuser in the professional arsenal.
Workflow and Mounting
250 is typically stretched in grip frames: 4x4 frames (approx. 1.2m x 1.2m) for single individuals, 6x6 frames for two-person scenes, 12x12 frames for group scenes, or as an "overhead silk." The distance between the diffuser and the light source affects the quality: close to the spotlight = more point-light character retained, far away = larger apparent light source = softer light. For maximum softness: position 250 as close to the subject as possible (but outside the frame).
Combinations and Alternatives
250 can be stacked: 250 + 216 results in an effect similar to 251 with finer falloff. 250 + 1/4 CTO creates "Warm Soft" for an evening mood. In extreme heat: Rosco Tough Silk or Lee HT series as an alternative. For budget productions: polyester shower curtains can yield similar results but have less consistent quality. Modern LED softboxes with built-in diffusion are increasingly replacing 250 setups, but do not achieve the same control over light quality.