A light coloured turban with brown/black edges means the man isn't married (no one to wash turban). It isn't a strick thing, but certain colours, and styles of tying are popular to certain areas. Green turbans are for Hajis, many times Shai people (especially clergy) wear black, etc, etc...
I stay in touch with many of the people in my photos, but these 3 were friends of a friend.
Dmitry asked really good question, because he's another shaitany. I also wonder if you guys maintain correspondence ?! I always wanted to ask the question, does colour of turban make any statement or it's just matter of personal preference ?