The famous "Surrender Dorothy" sky writing scene was done using a tank of water and a tiny model witch attached to the end of a long hypodermic needle. The syringe was filled with milk, the tip of the needle was put into the tank and the words were written in reverse while being filmed from below.
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Almost 50 years after the release of this film, Margaret Hamilton revealed her approach to the character of the Wicked Witch in an interview with Fred Rogers for Mister Rogers' Neighborhood (1968). Hamilton saw the Witch as a person who relished everything she did, but who ultimately was a sad, lonely figure - a woman who lived in constant frustration, as she never got what she wanted (this is, in fact, the basis of the novel and musical "Wicked," in which the Wicked Witch of the West is portrayed as an unfortunate protagonist). In the same interview, Hamilton also famously donned the original Witch costume to explain that the witches were only make-believe, and that children shouldn't be afraid of them.
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The film's running time was originally 120 minutes. Producer Mervyn LeRoy realized that at least 20 minutes needed to be deleted to get it down to a manageable running time. Three sneak previews aided in his decision of what to cut. The original film in its entirety was only seen once by an audience in either San Bernardino or Santa Barbara, and it was the only time the famed Jitterbug number was seen by the public. After this preview LeRoy cut the aforementioned Jitterbug number and the Scarecrow's extended dance sequence to "If I Only Had a Brain." A second preview was held in Pomona, where the film ran 112 minutes. After the preview LeRoy cut Dorothy's "Over The Rainbow" reprise, a scene in which the Tin Man turned into a human beehive, and the Emerald City reprise of "Ding Dong, The Witch is Dead," as well as a few smaller scenes and dialog, notably two Kansas scenes in which the Hickory character was building a machine to ward off tornadoes, as well as dozens of threatening lines by the Wicked Witch of the West. By the third preview, held in San Luis Obispo, the film finally was down to its 101-minute running time, where it has remained ever since.
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