[ccp4bb] on the contour level in Coot

[Smith Liu]

Dear All,
 
For the contour level in the Properties in the Dssplay of the Display Manager 
in Coot, the contour level should be exacly the sigma value we see in the 
published crystallography paper, am I right? But I have paid attention to a 
paper which has a sigma level of 6-7 for its densty. Will you please explain 
why the sigma can be so high and how can we make it so high?
 
Smith