Photography
What speed film should I choose?
The film speed indicates relative sensitivity to light expressed as an ISO-speed number. The higher the number, the more sensitive or "faster" the film; the lower the number, the less sensitive or "slower" the film.
A fast film requires less light for proper exposure than low-speed film. Graininess and sharpness are generally best with low-speed films. Graininess is the sand-like granular appearance given to an image by the structure of the film's light-sensitive emulsion. As film speed increases, graininess increases.