Free screen capture device that has suitable note
I simply downloaded and install the Snagit Beta for Mac, free in the meantime, I'm certain it will certainly set you back when it appears of beta. Until now it has every little thing I was requesting for other than the lowering attribute. It has a couple of various other wonderful attributes too.
LittleSnapper (not free) from Realmac Software does these points plus it has arranging attributes and also internet capture attributes, with resource code.
It's preferable for internet or various other sort of developers, probably, yet it has these note attributes.
A free device for rapid note (although I do not assume it has dimming or obscuring) is Skitch (stated by others below too) which is or else really hassle-free for rapid procedure.