Dave, Don't know what you mean by a proper rainbow, but my Color Tree may be of help: (URL) Lim also keeps a stack of 2x4 bricks in progressive colors: (URL) that helps, Clark (...) (22 years ago, 4-Jan-03, to lugnet.general)
(...) were looking for a chart displaying the spectrum of visible light... as seen in a rainbow or perhaps as split by a prism. Maybe something like this? (URL) hope that helps, Allan B. (22 years ago, 4-Jan-03, to lugnet.general)