Contrary to what you might be thinking, combi blinds (also known as rainbow blinds) are not the multi-coloured blinds that you have in mind. To be fair, this type of window blinds may come in many colours depending on your preference, but the main reason why they are called rainbow blinds is not because of the range of colours, but because of the function it offers.
Combi blinds are much different from traditional blinds. Traditional blinds typically have only one layer of fabric or material but the combi blinds consist of two layers of material—most commonly one layer of polyester and a perforated material. The perforated layer is the layer that allows sunlight to enter the room through its punctuated surface. This mechanism allows you to be able to control the amount of light filtering into your room, without compromising on your privacy.