Thanks for all your help with the contour problem. In the end I did levels=(10)(100)(1000) etc. as some of you suggested - thanks. The only problem with this is that for some reason if I have intervals like say 1.5e-9 and 1.5e-8 etc. the range values are written as 1e-9 and 1e-8 on the colour bar which is strange and annoying. Alice