Lightly Gold Plated Statehood Quarters

Hi again,

I'm probably posting in wrong place but still trying to navigate site.

At any rate, he's my question: Why are some early Statehood Quarters have a light gold color albeit uneven gold tint to them? I am aware of the 24k plated ones and have those but same years ,same sets have D,P, then finally the actual 24k plated ones and 98% of the D and P quarters have that gold tint but not the deep 24k ones. I also found an error on a New Hampshire quarter in the same set. Thanks for any knowledge on these.

I'll post some pics once figure out cropping.