One of the great things I love about photography is playing with light.
All the visual effects in the shot were created in-camera.
This particular image uses a number of techniques.
To start off with, the camera's shutter speed was set at a 1/2 second, fstop was at 7.1 and ISO 320.
I have a LED batten in the studio which I covered in blue, green and yellow gel to create that 'swing' of light. I had a strobe setup on each side of Sara and using a blue on the left and a red on the right. The right side strobe was shooting through a window blind and you can just see the effect come through on the right hand side of the image. There was more of the 'blind' effect but I have cropped the image to make it a tighter shot.
Because the shutter speed was so slow, the 24-105mm lens I was using had an ND8 filter on it.
During the shoot and with the slow shutter speed, Sara constantly was moving and my assistant with the LED batten taped to a broom handle furiously waved around the light, I would slightly move my camera each time I pressed the camera trigger. I had the I had the flash trigger in my hand and I fired the strobes manually.
This camera movement technique is what created those gold trails. I have no idea what created that cutout ghost effect in the 'light swing' on the right of Sara but I do love that effect.
In post, I had a bit of a play with the tones and also removed the broom handle that the LED light was on.
I have had many discussions with fellow photographers about that silhouette cutout in the swing light beam on the right and no-one seems to know why that occurred including myself.