Colour should be used to make the spreadsheet more user friendly and such.
Here are the guidelines that I tend to use.
All of my Row headings are bold and often in stronly contrasting colours
such as yellow text in a Dark Blue background. The rest of the sheet will
normally be in a pale yellow as that is easy on the eyes and does not print.
Column headings will often be in pale green or such. Use colour to group like
thinngs to gether. Where I expect the user to fill in info I leave that white.
The biggest thing in my opinion is to come up with a style that is
consistent and predicatble. This makes your projects more readily accepted as
they are easier to follow. In total I only use at most about 5 colours. They
are applied consistently in every spreadsheet that I do.
