grayscales

when we convert a color image into grayscale, we lose information about the original image. instead of tracking the red, green, and blue channels for each pixel, we only keep track of the luminance -- how light or dark a pixel is, a value between 0 (black) and 255 (white).

to convert a colored pixel into a grayscale pixel, rendering algorithms take advantage of how our eyes see color to create more natural images. rather than simply average the red/green/blue values of an image, we weight them according to how sensitive our eye is to each color. we're most sensitive to green light, so the green portion of an image contributes the most information to the grayscale version, next red light, next blue.

using the CIE 1931 standard for computing luminance, I've reconstructed images below so that all of the pixels in the image -- despite having distinct color values -- have the same luminance, and thus appear identical in grayscale. there are only so many standard colors that have the same luminance. the palette for each image is also produced below.