Of all of the wonderful elements that made The Wizard of Oz shine, one of the most memorable is its clever use of color. While the 1939 film was not the first to be shot in color, its bright production design and saturated palette made it stand out.

So why did the filmmakers decide to shoot Oz in color and Kansas in black and white? For one, the original book by L. Frank Baum deliberately describes Kansas as colorless, filled with “the great gray prairie,” “the house […] as dull and gray as everything else,” and “the sky, which was even grayer than usual.” Baum even paints Aunt Em and Uncle Henry as drearily monochromatic.

Shooting in Technicolor was an obvious choice for the filmmakers. They even made some changes to the source material in order to take advantage of color film. For instance, Dorothy’s silver slippers became bright ruby, designed by the MGM costume designer known simply as Adrian. The filmmakers paid so much attention to color that it took days to settle on a shade for the yellow brick road. Unfortunately, the color technology at the time required extremely bright lighting, which meant a lot of hot studio lights. On the set of The Wizard of Oz, temperatures were reported to be up to 100 degrees!

The most fascinating use of color film might be when Dorothy first enters the Land of Oz. After she lands, one complete shot over her shoulder shows Dorothy walking from her black and white house into colorful Munchkin Land. There’s no trick photography here—the whole scene is actually shot in color! The inside of Dorothy’s house was painted in sepia tones; since you can’t see Dorothy’s face here, Judy Garland’s body double is used for the first half of the shot, wearing sepia makeup and clothes. As “double” Dorothy opens the door and backs out of frame, Judy Garland walks into the shot, entering the radiant, full-color set!