21. The use of technicolor made filming a learning process for cast and crew
Technicolor was a technology which was less than 5 years old at the time of the filming of The Wizard of Oz, and the decision to use it for the color portions of the film created numerous difficulties. Heavy and hot, bright lights were required on the set and temperatures often exceeded 100 degrees. The heavy costumes worn by the actors made them hot and uncomfortable, especially those of the Scarecrow, Lion, and the Munchkins.
Blue did not show up particularly well in technicolor at the time, which is why the Munchkins of the film eschewed the favorite color of their counterparts of the printed page. Dorothy’s famed blue and white checked gingham dress was actually blue and pink, with the pink fading to white under the process. The oil used on the Tin Man too did not photograph well. Chocolate syrup was substituted for the oil, which Jack Haley found more pleasant when his comrades oiled him about his mouth.