The IMAX format is generically called 15/70 film, the name referring to the 15 sprocket holes or perforations per frame. The film's bulk requires horizontal platters, rather than conventional film reels. IMAX platters range from 1.2 to 1.83 meters (3.9 to 6.0 ft) diameter to accommodate 1 to 2.75 hours of film. Platters with a 2.5 hour feature film weigh 250 kilograms (550 lb). IMAX uses ESTAR-based print film in their 15/70 rolling-loop film projection systems.
Silicon dioxide, also known as silica (from the Latin silex), is a chemical compound that is an oxide of silicon with the chemical formula SiO2. It has been known since ancient times. Silica is most commonly found in nature as quartz, as well as in various living organisms.
Silica gel is a granular, vitreous, porous form of silicon dioxide made synthetically from sodium silicate.Silica gel is tough and hard; it is more solid than common household gels like gelatin or agar. It is a naturally occurring mineral that is purified and processed into either granular or beaded form.n this form, it is used as a desiccant to control local humidity to avoid spoilage or degradation of some goods. Because silica gel can have added chemical indicators (see below) and adsorbs moisture very well, silica gel packets usually bear warnings for the user not to eat the contents.