Transparency (projection)

As Overheadfolie suitable for overhead projection, transparent film made writable or printable polyethylene terephthalate is called. Although today more and more computer-based presentation techniques are used, are overhead transparencies for business and schools still important.

Root word, manufacturing, types, and related films

The word parts are in English and Latin: overhead over the head ( projected ) and folium for leaf.

The films are - like others - made in cars, have a thickness of about 0.1 mm and a format of 21 x 29.7 cm (A4). They are usually (depending on quality ) available in packs of 20 to 100 pieces.

They are available in different versions: To describe with special markers, heat resistant for copiers and laser printers, coated ( with gelatin which absorbs the ink and holds it until the water has evaporated ) for inkjet printers ( or color copiers that are based on inkjet technology ). It is not uncommon in offices or schools to the fact that have an unsuitable film is placed in the copier. This then melts in the hot fuser, glued them, wraps around the rollers and then usually requires removal through the Service or cause equipment damage.

Similar - only most flexible - films are in printing technology, used for the thematic " layers" of maps and for the light- sensitive layer of movies.

In contrast, packaging and construction films of other materials, because they must be against tensile forces weatherproof and stable.