Tonight we spent a few hours finalizing the contextual tab colors for Office 2007.
As you may have seen in pictures of the new UI, each set of contextual tabs has a color associated with it. This helps to uniquely identify each tab set for familiarity's sake as well as to group related tabs when you're using two sets of contextual tabs at once (such as a picture in a table.)
We have seven colors to distribute among the many contextual tab sets: yellow, orange, red, green, purple, blue, and teal. Because we have far more than seven sets of contextual tabs, certain objects have to share colors. In addition, certain colors (such as yellow and purple) stand out more than others (blue, teal), so we want to ensure that the most popular objects have recognizable colors. In early testing, we found a strong correlation between visible contextual tab sets and discoverability/usability of the tools.
Choosing colors for Contextual Tab sets
To avoid duplication in practice, we have a grid of object types vs. applications that we use to figure out which objects can be used in conjunction with one another. Then, we ensure that the objects that are most commonly used together don't share a common color.
We used data from Beta 1 and Beta 1 Technical Refresh to inform the decisions about the contextual tab sets that were most frequently used. For instance, it turns out that "Header & Footer Tools" in Word is used a lot more than we thought, so the fact that in Beta 2 these tools use the blue color is probably not the right thing.
The contextual tab headers up in the title bar are called "flags" by the way. I can't remember why now, but that's what we call them.