I'm not really sure what spraying it would have done as far as the color, I think it might have kept it more black... I'm not sure what color the ash would make it other than grey. I haven't worked with a lot of dark colors and my last try with black was a vanilla bean disaster. This was a black oxide from BB...recommended to me after the vanilla bean disaster.Oh that is very cool. What would spraying it have done to the color? I'm glad you didn't because those variations in the grey are gorgeous.