User blog comment:FairyRaven/Fairy Tail Chapter 407: All for My Demise, Review and Commentary/@comment-24536822-20141102062202/@comment-7418318-20141102081052

Maybe it's the other way round. We've seen it appear when used and then disappear when not in use before, so maybe it's not fully emerged yet.

Or it might have a white glow-effect put on top of it, which would make it a bit less visible in grayscale. Something like this for example.