Hi Folks, 

I see on the tutorial websites that when voxels are added to wm.mgz or brainmask.mgz, the new voxels are given a value of 255; 

while when voxels are deleted, these locations are set to 1. 

https://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/WhiteMatterEdits

Can the deleted voxels can be set to 0 or they have to be set to 1;

Or is 0 used to differentiate the background voxels from brain voxels ? 

Thanks

Mehul