Questions about colors

Here are a few more spider web photos taken in our backyard on 6 July 2017...along with a few questions!

First, my favorite color combination from today — in the center strand, check out those bronzy areas with the greens and blues!

 

Second, while reviewing images I noticed one strand that stood out.  Most of the strands in this web displayed many colored stripes.  But one in the photo below showed broader, more uniform areas and gradients of color, without narrow stripes.  Why did this strand have a different pattern?

 

And third, most of the colored stripes along the strands seem to be made up of one color (I think, but I could be wrong).  But I noticed a couple today that appeared to be multicolored.  In the image below, see the ring below the arrow that shows a variety of colors. What causes this?

 

I have lots of questions about the colors created by these spider web strands!