Requirements
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The human eye detects brightness not liniear but logarithmic. And it adapts to the brightness level. When you come out the light may seem a pitch dark room, but if you wake up at the same Lichtverältnissen, same room seems much brighter.
Even the smallest gaps break the absolute darkness.
Who wants such a thing as absolute darkness, comes to a roller shutter or a blind not around with management and end rails. The gaps that inevitably arise in a curtain, preventing the absolute darkness.
For Curtain
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The substance of the process is in three layers but very light and flexible. It is not as hard and stiff as curtains for darkening rooms. Thus, as used for example in Aulas.
The curtain can be pushed together compact and runs easily on the curtain rail. The curtain is easier than the cumbersome Abdunkelungsvorhängen from Aulas.
However, the curtain is not absolutely tight. That means it depends on the color of the curtain to. I bought twice this curtain, a. In khaki and two dark blue
The curtain in dark blue gives the window a dark area if one occurs very close to the curtain, you see it shine through easily. Overall, a very good blackout.
The curtain in Khaki darkens the room from though, gives the window, however, a bright surface. Thus, the rough is not really dark. But even in Khaki the curtain is absolutely opaque.
Expectations
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Who wants to have a room to really pitch dark, as I said should get a black-out blind with guide and end rails. When one sealing the gaps between the wall and rails and selects a 100% impermeable material, penetrates no more light.
With a curtain you have no chance to reach the side without obstruction. The gaps between the wall and curtain let through too much light, even when the curtain fabric is 100% tight.
This curtain is a practical compromise between handling and blackout.
The dark colors can be achieved very good blackout. Because when you open the curtains can be put together very compact, does not interfere with the dark color too much.
With the lighter colors, the brightness greatly reduce, but you get a room not really dark. Who wants a light curtain without transparency, has to look for another curtain
