Interactive White Balance Adjustment for Photographic Images
Due to different lighting conditions, white or gray areas in a photograph may not be displayed as neutral white or gray. White balance correction rescales the pixel values in the image in order to make gray areas display correctly.
This Demonstration lets you adjust the white balance of the entire photograph by analyzing a presumed gray pixel in the image and adjusting the remaining pixels proportionally. A pixel with red, green, and blue intensities is assumed to be neutral gray when .
Putting the locator in the original image on top of a pixel converts it in the right image to neutral gray and recalculates the remaining pixels, making the complete image "white balanced."