A projection display uses a light modulating device to modulate, in accordance with image data, light radiated from a light source, project the modulated light onto a screen, and display an image. The projection display separates a unit of time configuring the image data into an effective light time when the light modulating device can express the light as an image on the screen and an ineffective light time when the light modulating device cannot express the light as an image on the screen. The projection display increases the power supplied to the light source during the effective light time over the power supplied to the light source during the ineffective light time.