I'm new to restoration; any help would be appreciated. The picture below shows my blade after it's been run across my buffing wheel during first phase—using 80 grit grease-less compound. I paused as soon as I saw that part of my blade was reflecting the buffing-scratches differently. I'm unsure if this part of the blade has just been buffed more than the rest, or, is this temper loss causing color change. It was very hard to get a photo of the area that looks discolored; look closely where there's a faint white circle. Is this what overheating looks like? I'm using 4" cotton sewn wheels with a 3450 rpm machine; I am aware that this rpm can heat a blade quickly. Thanks for any help.