Patina or Coloring?

[Wet-Skunk]

I'm currently collecting the Tuttle Silver Co., Onslow pattern sterling silverware. I've noticed on a few of the utensils, the scrolling has black in the groves, where some do not. Fresh out of the original factory plastic, they are black in the grooves. Is this a patina, or a color they add for contrast? Does the lack of the black in the grooves devaluate them? I noticed that on some, it comes off over time.

[JLDoggett]

Many manufacturers oxidized the flatware blanks before stamping them. Usually this was done on patterns where they wanted the contrast as part of the pattern. I believe this is what you have.