The `negative reaction'

Let us summarize what happens in the last scene of the episode.

• Galesco is suddenly taken to the police station, where he is waited for by Columbo, who receives him not in his office but in a kind of repository containing shelfs full of objects (see figure 6), including the cameras in question, a few of which are visible behind Columbo, although nobody mentions them.
• Columbo starts arguing about the rest of the newspaper found in Deschler's motel room and used to cut out the words glued in the kidnapper's note. The missing bits and pieces support the hypothesis that the collage was not done by Deschler. Galesco, usually very prompt in suggesting explanations to Columbo's doubts and insinuations, is surprised by the frontal attack of the lieutenant, who until that moment only expressed him a series of doubts. He gets then quite upset.
• Immediately after, Columbo announces his final proof, meant to destroy Galesco's alibi. He has prepared a giant enlargement of the picture of Mrs Galesco taken by the murderer just before she was killed. The photograph shows clearly a clock indicating exactly ten (A.M.), time at which the lady had to be with her husband, while Deschler had a very solid alibi, that morning doing the driving test to get his licence.
• The expert photographer refuses this new reconstruction, on the ground that, he claims, there is a mistake in the enlargement, in which, he says, the picture has been erroneously reversed, thus transforming the original 2:00 (P.M.) into 10:00 (obviously, the analog clock had no digits, but just marks to indicate the hours). He asks then Columbo to check on the original.
• But Columbo acts very well in pretending he destroyed the original by accident when he was in the dark room to supervise the work (his often goofy way to behave makes the thing plausible).
• This clever move is able to stress the otherwise always lucid Galesco, who suddenly thinks he is going to fall into a trap, based on a false, incriminating evidence fabricated by the police. He gets then so nervous to loose control and, with a kind of desperate jump of a feline who sees itself lost, does his fatal mistake.

  Figure: The discarded photograph in Columbo's hands.

  
• Suddenly he has a kind of inspiration. He says the negative can prove the picture has been reversed.³² Then he rapidly goes to the shelf, displaces one camera and, with no hesitation and no sign of doubt, he picks up the one he used, that was visible, but cleverly placed in the back of others. Then, he opens that kind of old Polaroid-like camera and shows the negative inside it as the prove the picture was reversed and his alibi still valid.

But according to Columbo and his three colleagues, as well as to any TV-watcher, the full action incriminates him. [Finally, although the confession is irrelevant here, he realizes his mistake and his loss - murderers in the Columbo series have usually some dignity.]

Figure: Final photogram of Negative Reaction. The incriminating camera is on the desk. The remaining twelve are in the shelf just behind Columbo's head. Desk and floor are full of the bits and pieces of the newspaper from which the lieutenant tried to reproduce the kidnapper's note.