Laminating films have numerous characteristics to consider in determining which film is the right choice. Film construction, size, gauge, finish, and core size all need to be considered with a specific laminator and application in mind. For example, if you are planning to laminate laser-printed copy paper for sheet protection, and you have a 27" school laminator, then you would use a clear polyester-based 1.5 mil film 27" x 500' on 1" core.

Film construction will always have two components: the plastic and the adhesive. The most commonly used film base is polyester, which produces a high quality, clear laminate with the highest rigidity. Polypropylene is a clear, softer base, and is mainly used for one-side lamination (book covers, for example). The adhesive component of film may be a low density resin which melts at a high temperature and generally produces the most economical product. Also available are premium grade co-polymers, which require a lower temperature for bonding, and blended co-polymer adhesives, which have the lowest melt temperature. Lower melt films are important for documents that are more sensitive to high temperatures, and for the best adhesion to inks with a high moisture content.

Film size (width and length) will be determined by the type of laminator you are using and by the dimensions of the product you are laminating. In general, you can use film narrower than the size of your laminator but no wider. (For example, you can use 25" film on a 27" laminator, but nothing wider than 27".) The length of a roll is constrained by the diameter of the roll, which must not be too big to fit on your laminator. Film gauge and type of laminator are the primary determinants of roll length.

Film gauge is the thickness of the film, measured in mils (1/1000th of an inch). Film gauge is commonly expressed as the ratio of polyester to adhesive. For example, 3/2 film has 3 mils of polyester and 2 mils of adhesive and a total thickness of 5 mils. The higher the ratio of polyester, the more rigid the laminated product will be. If you laminate two identical pieces of a product using 3/2 film on one piece and 2/3 film on the other, both laminated products will be 5 mils thick. However, the product laminated with 3/2 film will be more rigid.

Film finish is one of the most important laminate attributes for commercial applications. While the widest application is for an economical clear (glossy) finish, films are also available with matte, satin, and crystal or textured finishes. Factors such as glare reduction, scratch resistance, and visual appeal are all important in print finishing, signmaking, and diplay production.

Roll core size is the last variable in film selection. This is determined by your laminator's mandrel size, which can be found in the laminator's specifications. In general, most school and light commercial laminators use film with a 1" core. Older models and a few of the mid-size laminators may use 2-1/4" core. Most of the industrial laminators use film with a 3" core.