-I do see it on the edge of a single finger.

-I agree, also I can only observe the effect when focusing on the gap

-sure, but weirdly the effect has to be wavelength dependent, but there are no color fringes.

I think this is something else, but haven't figured it out yet.

Interesting, I can only see the bands when holding my fingers very close to my eye, and _not_ focussing on it. If I hold my fingers far enough to be able to focus, I don't see them. Maybe my eyesight is not good enough. Focussing on a single finger, I see that the border has a green tint to it.

I agree that there's no colour in the fringes, which is unexpected for white light interference.

>-sure, but weirdly the effect has to be wavelength dependent, but there are no color fringes.

I do think you can get colour fringes in some circumstances. Try doing it in a dark room with a bright light coming through a small gap (e.g. between curtains). Like:

                                |
                                |                    (dark room)
                                |

    light source - - - - - ->- - - - - - - - - ->- - - - - - ->- - - - - - - - - ->  eye
                                                                       |
                                |                                      |
                                |                                      |
                                |                                    finger
                        small-ish gap (1-5cm)

IIRC you can get colour fringes between the finger and the top edge of the gap behind it.

EDIT: I just tested it, there is definitely a rainbow spectrum between the finger and the gap. The gap side is blue and the finger side is red. Not sure if this is the same effect as the article though.