Window blind

Persian blind detail, showing how slats are connected

The most common window blinds are Persian blinds, which consist of many horizontal slats, usually of metal or vinyl, connected with string such that they can be rotated to allow light to pass between the slats, rotated up to about 170 degrees to hide the light, or pulled up so that the entire window is clear.

A Venetian blind has horizontal slats, located one above another. Venetian blinds are basic horizontal slats made of metal, vinyl, PVC or plastic. Wood slats are sometimes used but in the US these are now usually referred to as wood blinds. Venetian blinds are suspended by strips of cloth called fabric tapes, or by cords (i.e. Ladders), by which all slats in unison can be rotated through nearly 180 degrees. The slats can be rotated such that they overlap with one side facing inward and then in the opposite direction such that they overlap with the other side facing inward. Between those extremes, various degrees of separation may be effected between the slats by varying the rotation. There are also lift cords passing through slots in each slat. When these cords are pulled, the bottom of the blind moves upward, causing the lowest slats to press the underside of the next highest slat as the blind is raised. A modern variation of the lift cords combines them with the rotational cords in slots on the two edges of each slat. This avoids the slots otherwise required to allow a slat to rotate despite a lift cord passing through it, thus decreasing the amount of light passing through a closed blind. Slat width can be between 16 and 120 mm, with 25 mm being a common width.

Related patents were taken out in England by Gowin Knight in 1760[3] and Edward Beran on 11 December 1769,[4] but Venetian blinds were known to the French long before then. In 1761, St. Peter's Church, Philadelphia had such blinds.[5]

In the late 19th and early 20th centuries, Venetian blinds were widely adopted in office buildings to regulate light and air. A large modern complex in the US that adopted Venetian blinds was Rockefeller Center's RCA Building (better known as the Radio City building) in New York City, completed in the 1930s. One of the largest orders for Venetian blinds ever placed was to the Burlington Venetian Blind Co., of Burlington, Vermont, which supplied blinds for the windows of the Empire State Building in New York City.[6]

In the last few years some companies reinvented the traditional Venetian blind placing it inside the double glass unit of the window. This new type of blind overcomes the problems related to damaging and fouling. Usually magnets are used for motor transmission in order to preserve the sealing inside the insulating glass.

Pleated blind

Unlike horizontal blinds, vertical blinds are less likely to collect dust because they stand vertically. Since they draw to the side rather than lifting and lowering, they are easier and faster to operate. They operate best on patio doors and sliding windows that slide from side to side. In the 1970s there were few choices of fabric- usually beige or white, which had to have stiffener embedded to prevent fraying, rather like on roller blinds fabric but using a thicker textile.

Vertical blinds became available in flat plastic (PVC), fabric, embossed PVC, faux wood materials, metal, wood and also S-curved slats. A more modern modification is to offer them with woodtrim at top and bottom- sometimes midway as well- and these are usually described as 'Japanese Vertical blinds' because they are often co-ordinated with Japanese style Shoji blinds using the same timber. Vertical blinds were most popular in the UK during the 1990s, since when sales have slowed as they lost popularity with a younger generation.

Stationary vertical blinds are hung in the doorways of some homes and businesses which generally leave the door open. Movement of the blind may signal a change in air flow, or someone entering the doorway. More commonly however, these vertical blinds are made of thick plastic. In the cold rooms of food businesses, this slows the heat leakage into the cold room. In warmer climates, vertical blinds discourage flies and some other insects from entering the building. In certain areas of the UK window blinds are used to disguise the fact that offices have PCs in them and are used as a burglary deterrent.

Roman shades are a type of window blind used to help block out the sun. Although often called blinds, these are actually referred to as "shades" in the window covering industry. They are often referred to as Romans or Roman blinds in the UK. When opened, the Romans stack up evenly; when covering the full window height, they are smooth without overlapping.

Roman blinds can be purchased with a blackout lining on the back to fully block out sunlight. However, there will always be small light gaps on the edges of the blinds if mounted on the inside of the window frame or peaking out from behind the blind if mounted on the frame around the window.

Unlike other blinds, such as certain fabrics used for Roller Shades, Vinyl Vertical blinds, or Vinyl Horizontal blinds, Roman Shades are not an ideal option for areas with a lot of moisture, such as bathrooms or windows above the kitchen sink.

Based on Japanese shōji, shoji blinds are normally thinner so they can be top-hung on a panel-blind track- 17mm thick consisting of a laminate of Obeche timber for lightness and strength. The wood has to be air-dried for stability as the slightest warping will distort the whole panel. No bottom track is required and almost any fabric or paper can be employed, although 90% of all shoji blinds use white polyester to imitate 'washi' Japanese paper.

Other varieties of window blinds include mini blinds (typically aluminum, Venetian-Style blinds with very narrow slats, usually 1 inch (25 mm) wide), micro blinds (usually ​¹⁄₂ inch (12 mm) wide), louvers, jalousies, brise soleil, Holland blinds, pleated blinds, and roller shades.

Blinds (otherwise referred to as "shades") made of fabric can either be rolled up (on a tube; Roller shades), folded up (Roman shades) or pushed up in an accordion style (Pleated and Cellular shades). Many fabrics are used including cotton, polyester, wool, viscose and silk to create these shades. A silk cloth can be present or embroidery stitch, which will give tissue varied terrain.

Custom made roller blinds come in blackout, room darkening, light filtering and sunscreen/solar fabric options. They are mounted on a metal headrail and operated with a side chain or spring mechanism. Cheaper and ready made blinds often come with a PVC pole instead of a metal headrail. They are widely used in Australia, Spain and many other countries.

Wooden blinds are generally known as Venetian blinds. A number of horizontal wooden slats are joined together by corded pulleys which can either gather all the slats at the top of the window to reveal the view or simply angle the slats while allowing some light to travel through the blind yet retaining some level of privacy. Wooden blinds come in a number of finishes (determined by the type of wood used, which ranges from painted to most types of solid oak varieties) and sizes (determined by the width of each slat which is usually available in one of three widths—25 mm, 35 mm or 50 mm). Wooden Venetian blinds are also available as vertical blinds. These are usually made up of wider slats and operate in virtually the same way as their horizontal counterparts (i.e. instead of being drawn upwards to reveal the window, the draw to one side gathering in a vertical bunch).

Pinoleum blinds are made up of small wooden twigs laid horizontally which are joined together by vertical threading. The resulting weave is, as a result, only flexible vertically and can be drawn upwards once manufactured as a roller blind or in a similar fashion to a Venetian blind. Conservatory blinds are often made with Pinoleum.

In Malaysia, an outdoor blind is sometimes called a "chik". The word was carried over from India by the British during the colonial times.

Faux wood blinds are an alternative to real wood blinds. Faux wood is also known in some countries as Plaswood (Plastic & Wood). Made of a composite of man-made materials and natural wood particles, faux wood can be a less expensive choice than natural wood. These blinds have become more popular as the products have matured, becoming cheaper and more versatile at the same time offering more of a natural wood look. Current faux wood blinds are warp resistant, have UV ratings as high as 500 and come in colors that would be hard to find in natural wood blinds. Because of their resistance to warping, faux wood window blinds are suitable for areas with extreme temperature swings or high moisture, such as bathrooms and kitchens.

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  Faux wood blinds in use.
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  Basswood compared to plaswood/faux wood.

Venetian blinds, both horizontal and vertical, are available in a number of man-made materials (either resembling wood or metal or simply plastic). These are better suited to areas where moisture or direct contact with water is likely to cause a problem, such as bathrooms and kitchens. These blinds are often available with micro slats (as small as 16 mm or less). The result of smaller slats is that more have to be used to obscure the window completely. Conservatory blinds (i.e. ceiling fixed via a number of horizontal pulleys) are often made of man-made materials.