Hinged metal shutters mounted directly on light head — four movable blades. Precise feathering and negative fill without power loss.
The lamp head has four swiveling metal wings – the shutter or blade flag. Each wing moves independently in its guide rails, can be precisely positioned in front of the light source, and thus cuts light out of the image without reducing the overall intensity. Unlike a diaphragm, which dims evenly, here you are selectively blocking image regions. The wings are thin enough not to be visible in the shadow, but stable enough not to warp even under intense heat.
In practice: You set up a spotlight on an actor, but the light shouldn't fall on the wall behind them. Engage the shutter – done. Or the ceiling is too brightly lit, but you want to keep the actors. Engage a wing from above, and the ceiling disappears. The intensity remains the same because you are only creating a geometric cut-off, not diffusion. This is crucial: a diffuser would scatter and weaken the light; the shutter simply blocks the rays you don't need.
The four wings allow for combinations – two sides, top-bottom, diagonal cuts. With very hard light (Fresnel, PAR), you have to be careful: the cut edge is hard. If you need soft light, you place diffusion material directly behind the shutter openings or work with multiple lamps. Experienced grips position the shutters with millimeter precision – it's about image composition, not a makeshift solution. A well-placed shutter guides the viewer's eye, prevents overexposure, and costs zero luminosity.
Caution: The wings can warp under intense heat radiation – therefore, check them regularly and do not keep them completely closed for too long. Some sets work with flags (stands with black or gray cloth) in parallel – quicker to handle, but less precise than shutters. Professionals combine both: shutters for light precision, flags for larger cut-offs.