Professional & Amateur Film
Some companies such as Kodak sell color film for professional and amateur photographers. Films that are designed for professionals are identified by the word professional in their names such as Kodak Vericolor III Professional Film. Amateur and professional versions share similar color quality, sharpness and granular characteristics. They also have emulsions consisting of various chemicals which change slowly with time.
All color films start to change from the day they are produced. As film ages, its color balance will change. Amateur films are made to age and reach their peak color balance a lot later than professional films. Film makers will allow for the time the amateur film will be stored, in the store and in the camera before being developed. The ISO speed given the film is adequate for calculating exposure under normal photography situations. Professional films are made to be very near their optimum color balance when they are shipped from the manufacturer. Professional film should be refrigerated or frozen until ready to use since refrigeration will keep the film near the optimum point until it's used.
Precise film speeds are given to professional films. The film is also designed for quick developing to prevent any significant color balance shift after exposure. If you are looking for film with optimum color balance and precise speed within about 1/6 f/stop, then professional film is ideal. If you are going to be away for an extended period of time without refrigeration or developing facilities you should use amateur film.
Professional film starts at about $5 a roll.