My 'light on' chart created yesterday, thanks to Vog TM, is looking good. I am now trying to change the time from a decimal, ie. 9:20 shows as 9.2, to the time 9:20. When I change the format of column B to time, the value of 9.2 changes to 4:48, which I assume is a calculation of 9.2! If I then change 4:48 to 9:20, the chart goes all to pot. All this is probably irrelevent as there is an easy way to change the format!