In "The Joan Baez Songbook," 1964 Ryerson, and 1989 Amsco, p. 28-29, she prefaces the song with acknowledgements to John Jacob Niles [the author??] and Jean Ritchie.
Yes, the Baez lyrics are brief. From the music in her book:

BLACK IS THE COLOR (Baez)

Black, black, black is the color of my true love's hair.
His lips are something wondrous fair,-
The purest eyes and the bravest hands,-
I love the ground whereon he stands.-

Black, black, black is the color of my true love's hair.

I love my love and well he knows,
I love the ground whereon he goes
And if my love no more I see,
My life would quickly fade away.

Black, black, black is the color of my true love's hair.

"Interested in the process of change" The material put together here pretty well covers it. I think the song is typical JJN, but make up your own mind.