* What and Where is This Picture * (and Bubble Colors partly explained)

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This is a picture of the top of a large bubble (9 foot/3 metre diameter maybe) with a dark forest behind it. The golden-bronzy colored part is near the very top of the bubble and the color is because the bubble is very thin on top. The liquid in the wall flows downward over time, so, the pinkish-purple part is where the bubble wall is thicker. The colors have to do with the bubble-wall thickness in relation to the wavelengths of those colors of light. The blue part is slightly thicker than the purple.

The un-cropped Photo:

The light blue part is white clouds in the sky reflected on the blue part of the bubble. The dark green "treeline" along the bottom edge of the "blue sky" is a reflection of the tops of trees behind me as I take the picture. I am in a clearing in a forest at the "main stage" of the Faerieworlds festival at Horning's Hideout near Portland Oregon, USA.

In the picture above, you can see the bubble colors are only easy to see when there is a dark background behind the bubble. You can also see the color bands alternating as the bubble-wall thickness varies by multiples of the wavelengths of those colors of light. Because the big bubbles are not usually a perfect sphere and are rolling and twisting as they float, the colors (wall thicknesses) are not usually simple patterns.

You may be able to see that, under suitable conditions and viewing angles, the sky is reflected on the top of the bubbles and again, but upside-down, on the bottom of the bubbles. The bubble-makers here are using cotton strings dipped in a bucket of bubble mix.