Figure 1: Retargeting from and to a dark display. Left: Image as seen on a 2 cd/m 2 peak luminance display. Center: Original image. Right: Bright image compensated for a 2 cd/m 2 display. When the original image is seen through a neutral density filter reducing luminance 100 times (2.0 D), it will match the appearance of the left image. When the right image is seen through the same filter thus simulating a dark display, it will appear similar to the original. Note that the seemingly exaggerated sharpness, color shift and brightness change are not perceived as such at low luminance levels. The images are best seen when the page is enlarged to 3/4th of the screen width and viewed from about 0.5 m for a 24 " monitor. Abstract The same physical scene seen in bright sunlight and in dusky conditions does not appear identical to the human eye. Similarly, images shown on an 8000 cd/m 2 high-dynamic-range (HDR) display and in a 50 cd/m 2 peak luminance cinema screen also differ significantly in their appearance. We propose a luminance retargeting method that alters the perceived contrast and colors of an image to match the appearance under different luminance levels. The method relies on psychophysical models of matching contrast, models of rod-contribution to vision, and our own measurements. The retar-geting involves finding an optimal tone-curve, spatial contrast processing , and modeling of hue and saturation shifts. This lets us reliably simulate night vision in bright conditions, or compensate for a bright image shown on a darker display so that it reveals details and colors that would otherwise be invisible.