Double Contrail

I wanted to make sure you could see the twin contrails left by a plane so I cropped the picture in Photoshop. Then I experimented with a duplicate layer.

The second picture is not realistic but I liked the contrast. The dark background was created when I used "Linear Burn" on the duplicate layer.

Contrails are formed of water vapor and are also called vapor trails. They are often pretty but may contribute to global warming.