Context: Relatively insensitive film, with a correspondingly lower speed index, requires more exposure to light to produce the same image density as a more sensitive film, and is thus commonly termed a slow film. Highly sensitive films are correspondingly termed fast films. In both digital and film photography, the reduction of exposure corresponding to use of higher sensitivities generally leads to reduced image quality (via coarser film grain or higher image noise of other types). In short, the higher the sensitivity, the grainier the image will be. Ultimately sensitivity is limited by the quantum efficiency of the film or sensor.

Question: What does the film's quantum efficiency limit? 
Answer: sensitivity

Question: What speed of film is produced by insensitive film? 
Answer: slow film

Question: What leads to lower quality images?
Answer: reduction of exposure

Question: What types of film are considered fast films?
Answer: Highly sensitive films

Question: What effect does highly sensitive film have on images?
Answer: reduced image quality

Question: What does insensitive film with a faster speed index need?
Answer: Unanswerable

Question: What does a sensitive film more of?
Answer: Unanswerable

Question: How is digital photography different from film?
Answer: Unanswerable

Question: Higher sensitivity leads to greater what?
Answer: Unanswerable

Question: What does a grainier image limit?
Answer: Unanswerable