In order to obtain these fantastic rainbows we use a specific material on the outside of our tubes. For this specific kind of rainbow we use this 2-way reflective metallic spandex. When you order it you get a pretty decent amount so it will allow you to create multiple tubes whether they be on t12 tubes or t8’s.
Personally I use a t12 tube and use scotch tape to attach the material to the tube.
In my personal opinion the fantastic thing about the rainbow material is that it can give a wide variety of effects depending on how you use it. For me I generally shoot in complete darkness using two flashlights with a low ISO and a high f-stop of 8 or 9 to get my desired effect. Zach however get’s different colors when he’s shot during blue hour and it turns out brilliantly. I don’t have his specs but here are a couple of his pictures on his instagram.
When shooting with this material in my experience SOOC (straight out of camera) you can see some slight colors from the material but not to the extent that you see in pictures after they’ve been edited in Lightroom or some other editing program. The biggest thing when it comes to these pictures is to make sure to boost the saturation and vibrance to really get the colors to pop out.
On top of this when it comes to the rainbow tube if it comes to other shapes other than a circle and straight lines I don’t find that it performs that well. It’s something that I need to continue to experiment with but that’s what makes light painting so grand! Thanks for reading!