Data sheets can be found for almost all film stock today. They detail the films characteristics, specifically how the stock reacts to light. Information regarding the contrast of the film is located on a graph called the characteristic curve.
The graph measures the films density as it is exposed to light. A steep curve would conclude a sharper contrast range. When the curve inclines gradually, the graph is indicating a low-contrast film.
Ortho and hicon film are known as high-contrast film stocks. They're characteristic curves are extremely steep, yielding dense blacks.
The contrast of the film can be manipulated with an appropriate developer. There are various developers that effect contrasts levels differently. Kodak's D-19 is considered a high-contrast developer, and Kodak's D-76 is for mild contrast and normal developing.
The length of time spent in the developer can affect the contrast considerably. Push is a term for creating a higher contrast; the method includes developing film passed the recommended duration. The term pull describes a shorter duration of development and will result in a lower-contrast film.