A visitor to the Microsoft newsgroups wanted his area chart to show a different color for positive and negative values. This is easy enough to do in a column chart. One technique is simply to use the Invert if Negative formatting option, the other it to make a conditional chart with one series for positive values and the other for negative values. Neither of these techniques works for area charts, but it’s possible to adjust the data to make an area chart with two series, one for positive and one for negative.
Del Cotter has written up a very similar approach in Excel area chart with colour invert if negative. It’s the first I’ve seen of his Information Ocean blog, but I’ve added its feed to my reader, and I’ll keep up with it.
