Of all the questions and issues surrounding the lamination of large format digital graphics, film selection is perhaps one of the toughest. Selecting lamination films is sometimes a complex process.
Price alone is not a good basis for making film-buying decisions either. Unless you know from experience that it will work on your media, buying the lowest price film can be a losing proposition. The cost of reprinting and refinishing the pieces ruined by using the wrong film is much higher than the extra cost of buying the right film at the start.
Here are some basic factors to consider:
- Films of the same thickness and appearance can often behave very differently when they are manufactured using different processes and base materials.
- Laminating films can be broken into two broad categories: hot (thermal) films, and cold (pressure-sensitive adhesive or PSA) films.
- Hot films can be generally classified as low-melt (about 210 to 260 degrees Fahrenheit) or very low-melt (about 170 to 210 degrees).
- Hot films are less expensive than PSA films, but are not appropriate for all applications.
- Be sure to choose the right adhesive for the job. Adhesive factors to consider include:
- Water-based adhesive vs. solvent-based adhesives
- Bond strength
- Initial tack and degree of permanence
- Clarity of base and adhesive
- Release liner material
- Match base and adhesive performance to the job
- Cast vs. calendered PSA film considerations:
- Cast film tends to be more expensive than calendered
- Calendered performs better when laminated to a flat surface
- Cast film performs very well on curved surfaces
- Be aware of the ratio of base material to adhesive layer
Dan Evans is a retired industry consultant with a deep background in laminating films. He first started in the computer and large-format graphics industries in 1979.