We started shooting another art series titled Alone (which you can read about here) and it provided a useful setting for cool lighting technique. Motivated lighting is a great way to sell a scene as more realistic, and you can use it to introduce colors or shadows into the scene. Our scene was a day hotel at night with a waitress zoning out while trying to cool herself down.
To use motivated lighting in this scene, we designed a set to have a window on one side for a large, soft key that would be balanced (I love cross lighting) with a sconce on the other side to provide a back light. That way we could have a blue-white light (I added full CTB to the source) through the window and have the sconce be a glaring yellow to contrast. Both of these elements would be in final shot and need to appear as if they were the light source, especially the sconce if it was going to be so (wonderfully) horribly yellow. The white balance on the camera was set to 5000K to push the color a bit more.
What I like to do in these situations to make the sconce appear “on” is to shoot a strobe/light directly down into it. For this application I used a head with a 3 degree grid on the front, and then taped a straw gel to the outside for the color. The light hits the glass of the sconce and illuminates it with that color, and creates a shadow down the wall that’s not terribly far off of what should be there. It also spills a little yellow about the set and wall surrounding the sconce.
This is useful for turning the light on, but I used an additional head with a 30 degree grid and straw aimed into the set, primarily at the talent for her back light. The grid helps keep the flare out of my lens, and shapes it nicely on the bed and floor elements in the surrounding set. I shot this one through doubled-up 1/4 silks to soften and spread it a bit to give it the right look. Both of these lights were sharing a pack and set to the same power level — about 1/4 power on a Profoto Pro6 pack in the B channel. I was shooting 1/125 of a second at f8 with the ISO set at 200.
So give that a try next time you need to turn on a lamp. It works great for table lamps too as you’ll light up the table they’re on as well!