The first window films were developed in the 1960s. They were (and still are) clear or tinted adhesive-backed products that allow viewing through the film with a minimum amount of distortion. The original films were dark and not all that transparent.
Digital printing has added a whole new dimension to the world of window film. A variety of print media designed for use on windows has proliferated in our industry. There are films for mounting on the inside of glass, and films for mounting onto the outside of glass. There are films that are opaque, translucent or transparent, and films that are permanent or removable. And there are also perforated films which allow viewing of a grahic on once side, but are see-through on the other. Let’s review some of the basics.
- Opaque Films—This type of films allows no light through whatsoever. They usually have a black or gray adhesive layer that blocks light transmission. These prints have to be installed on the side of the glass that they will be viewed from. If you want to read this type of film from both sides, you’d need to install the graphics on both sides of the glass.
- Transparent Film—Printing onto a clear, transparent film has several advantages over traditional white decals. The graphic can be mounted on the inside of the glass. By printing the image in mirror format with white backing sheet or white ink as the topmost layer, the adhesive side can be placed on the inside of the glass and seen right-wise from the outside.
- Layering Transparent Films—By placing a white opaque backing sheet between two layers of printed transparent film you can create an image that can be seen equally well from both inside as from outside.
- Etched Vinyl—This vinyl mimics sandblasted glass and can provide an attractive, distinctive window covering that also increases security by blocking people from looking through the glass while still allowing light to pass.
- Static Cling Vinyl—Cling vinyl is temporary, but can be used again and again. The material can applied to glass from either the inside or the outside, with clear and white products respectively available for these two purposes. The clear prints for the inside of glass are generally printed mirror-image, then backed with white.
- Perforated Window Film—This film, also known as window perf, can be placed right over the glass areas of cars, trucks, buses and buildings without seriously obscuring the vision of those inside, or the amount of light transmission.
The magic is simple. The film features tiny holes (perforations) that are spaced at regular intervals across the face of vinyl surface. The outside surface of the decal is printed with the required graphic, the inside (adhesive side) of the decal is black. These are mounted to the outside of the glass.
For inside mounting, a clear decal is printed mirror-image, then backed with white and black perforated layers. Different types of perforations patterns allow various amount of light to pass.