When first think of Alcatraz, it is reasonable that people would associate it with the prisoners it held. True, Alcatraz was "home" to some of the most feared and the most hated people in America. However, the role of guards in this prison should not be overlooked. They spent each day and night with these prisoners. They were a special group of citizens too. In the movie "Escape from Alcatraz", the director shows quite a few interactions between the prisoners and the guards. Through these interactions, the audience acquires an interesting portrayal of the guards.
In order to deal with some of the sliest prisoners in America, it is reasonable to picture the guards as intelligent. However, in this movie the guards seem to be very easily fooled. It might be a result from their arrogance and over-confidence. When Morris is trying to pass the metal detector while carrying two wedges, he brilliantly acts as if his plan is exposed by letting the guard take away the first wedge. Ironically, the guard notes that Morris is stupid from his seemingly simple-minded attempt. Another incidence occurs when a guard stops Morris for a instrument bag check. Morris cleverly dodges the check by tossing the suspicion toward West. From this scene, we see that Morris is the one who is on top of this mental game. He makes the guard think exactly what he wants them to think. He is manipulating the guards.
From the book, we learn that the guards are specially trained to detect any suspicion and see every prisoner as a possible threat. In general, they are still portrayed in the same way in the movie, even though they are fooled by Morris. The guards are shown as very cold-blooded. When a guard shoots a fast stream of cold water through a huge hose to Morris, the word "inhumane" instantly jumps out. Later when another guard takes away Doc's paintings and art equipments, he shows no sign of sympathy. This kind of portrayal is very close to what normal conceptions of the guards would be - cruel and apathetic.
After all, the details the movie adds in addition to the book are very interesting. The additional interactions shown in the movie make the movie much more intense and complex than the original book. The movie "Escape from Alcatraz" does a good job of telling the story of the famous escape and portraying prison life on the island.