The process of restoring color to black and white movies involves film colorization. This technique involves adding color to a picture, and it has evolved over time from hand-painting each frame to using computers to digitally color individual objects. The most recent method of colorization uses software to color each pixel, which is then blended together to create a continuous image. The original black and white film holds all of the brightness information, so the artist can paint large areas with a single color and let the original film handle the brightness gradients. This means that the artist might only have to add 10 or so actual colors to a scene. To speed up the process even more, interpolation is common.