spark plug reading?

[XS650D]

I have my 77 xs runnin pretty good but both cylinders seem to be runnin a lil different,one side the plug is grey the other side is light brown with a slight bit of grey on the very tip,does grey mean its running leaner or hotter or is brown color leaner/hotter,thx

 

[scabber]

Brown rich, gray is leaner with correct smoke ring is preferred.

 

[angus67]

personally, and I will prolly be flamed for this, but I always shout for a touch brown (rich) to have a cushion of safety.