Roll-up blind on balcony in Raval, Barcelona 
Part of the effectiveness of this filters lies in the fact that the group formed by the blind and the small balcony creates an intermediate space. Even when the doors of balcony are open, a place where the facades are so narrow (Raval district of Barcelona), the roll-up blind creates a space with a high degree of privacy, while allowing lateral sight to the street.
At the same time, the blind screens the solar rays while allowing ventilation to flow under the filter and through its holes.
The fact that the glass is translucent and not transparent also helps to reduce the feeling of exposure to the outside.