The more you know about a film's characteristics, the better able you will be to predict the outcome of your photographs. Look no further than the manufacturers themselves. Manufacturers such as Kodak, Fuji, and many others have been producing technical data sheets on their films for years. This is precisely where to find detailed information on the characteristics of the films you use. Now with the information firmly in hand, lets go through what's contained in the publications.
Color film is sensitized in three layers to red, green, and blue light.
The spectral sensitivity chart in your tech sheet will show the sensitivity of each layer in your type of film. For daylight balanced color film, the three curves will have similar shapes and some overlapping will occur. See the sample chart below.