In flash photography, the tricky part is to merge flash with ambient light.
As covered in Flashography – The Basics of Flash Photography, the main subject is exposed with the flash while the background is exposed with the available ambient light.
When you shoot at an attractive photo location, you can benefit from interesting light in the background. If the location is less photogenic, this has a negative effect on the result. But when you give the background a colour, magic happens. The colour accent creates a completely different atmosphere in the photo.
Coloured gel filters can be used for special effects. They are ideal for giving a colour effect to white walls or boring backgrounds. Gel filters are available as a cap that you snap on to the flash head or as a transparent colour film that you attach to the flash head with adhesive tape. The photo above was made by Jeroen van de Wetering during one of our workshops Off-camera Flash photography. Jeroen used three disconnected flash units and two different gel filters. The light setup below shows from a bird’s perspective the set up.
The flash without gel filter illuminates the model. The flash unit stands on a tripod and is aimed towards the face of the model.
The flash with a blue gel filter on the flash head illuminates the right side at the background.
The flash with a purple gel filter on the flash head illuminates the left side at the background.
The flash units to which the coloured gel filters are attached can make the intensity of the background lighter or darker. All you do is increase or decrease the flash power on your flashgun.