Hi,

You can not format individual gridlines. The work around is to add extra
data series for draw the line. Here is a collection of examples to
help you.

http://peltiertech.com/Excel/Charts/AddLine.html
http://tushar-mehta.com/excel/charts...nes/index.html
http://www.andypope.info/charts/averageline.htm
http://www.processtrends.com/pg_char...ontal_line.htm

Cheers
Andy

jones7288 wrote:
How can I change the color of certain gridlines "not" all gridlines? For
example, with a control chart - a yellow line for mu - 2sigma and a blue line
for mu - 1sigma?



--

Andy Pope, Microsoft MVP - Excel
http://www.andypope.info