Early VIC-II chips produced somewhat different colors than the later ones. In the earliest revisions the 16 colors had five luminance levels, i.e. brightness values. Black and white are the lowest and highest values, and the remaining 14 colors use three luminance levels that are evenly spaced in the brightness spectrum. Simply put, there are dark grey, medium grey and light grey, and all the colors are as bright or dark as these three shades of grey.
In later VIC-II revisions four intermediate luminance levels were introduced. Now there was nine luminance levels instead of the previous five. The palette with nine luminance levels is what most people consider as the normal C64 colors. From this article you can read all about C64 luminance levels and colors.
In this picture you can see how the different luminances affect picture that has been made for the “normal” C64 colors: Read the rest of this entry »