Here are the swatches from Andrew T. Young's article in Sky and Telescope. Each one is averaged over the face of the respective object. They are in the following pattern:

Mercury Moon Mars

Jupiter Io Titan

Uranus

White background

[img=http://img187.imageshack.us/img187/9541/planetcolorscg7.th.jpg]

Black background

[img=http://img187.imageshack.us/img187/3355/planetcolorsdarkbackgroyg7.th.jpg]

I had trouble getting a decent photocopy, either with the scanner or with my digital camera, so I eyeballed them, looking at the magazine under a light that made the paper look really white, and matching the swatches in my PaintShopPro software.

Mr. Young used the best available reflectance spectral measurements, including the Viking landers for Mars. He transformed the spectra into CIE coordinates to get the additive primaries, which he then converted to Munsell coordinates for pigments. With the assistance of some paint experts he was able to create the swatches, which Sky and Telescope reproduced as closely as possible with the halftone printing process.

Mr. Young reminded us that the Voyager cameras, for all of their marvelous imaging capability, were not reliable sources for the giant planets, because of their limitations in working the red end of the spectrum. Thus he used Earth-based observations. He omitted Saturn because of difficulty in distinguishing between the cloud tops and the rings with the available equipment, but added that it generally is similar to Jupiter in hue. He also omitted Venus, which he described as "brilliant white".