Nearly every photographer has spent a portion of a session bouncing from tree to tree, placing their subjects in the patches of shade that these saviors provide. After all, it tends to be one of the easiest settings to work in. Your subject’s eyes are relaxed, your camera’s meter is calm, and if you’re lucky you get to cool off too.
Naturally, I spend a lot of time in social media groups viewing photographer’s images taken in the shade while implementing off-camera flash. Time and time again, I stumble on images that have everything going for them, but fall victim to the same problem.
Shaded environments and flash are incompatible.
More specifically, flash is a daylight balanced light source, with a temperature of 5500K. Shade on the other hand is a higher temperature, ranging from 6500k-9000k depending on how deep the shade is. So how does this affect our images? Check out this photo of my friend Jake. This was taken in daylight, with his back to the light, so his face was in complete shade. We have a flash lighting the left side of his face, while the ambient shade is filling the right side of his face and body.
Notice how in the 5500K image, his right side looks as if he’s wearing a blue shirt, while his left side seems balanced and natural? That’s because of the disparity between color temperatures. The camera is balanced for 5500k, which matches the flash perfectly, however the cool temperatures of the shade affect his right side, even given the skin an unflattering tone. And if we look at the right side, the same image is pushed to 8900k to remove the blue temperature, but now the skin tones and whites are overly warm. There is no global image adjustment that we can do to fix this in post, and it would take a lot of extra time to accurately correct it.
This plagues a lot of outdoor images. Any time you are shooting into an outdoor background, your ambient fill light is going to show on your subject in some places, unless you completely illuminate your subject with flash. Fortunately, there is a really easy fix that you can implement to balance the flash with shade, or even use in some other instances for a creative effect that drastically changes the look of your images.
Enter, the CTB (Color Temperature Blue) Gel. By using a CTB gel, we can balance the flash color with the ambient color. By adjusting the color temperature, we will eliminate all the unwanted blue colors on the subject, and also have a more accurate background in shaded environments. Here’s a comparison between two images in the same spot; one with the flash without a gel (5500K) and another with a ½ CTB gel on the flash (7900K)
In the 5500K image with no gel on the flash, the greens look way more aqua, due to the Kelvin temperature of the background rendering far cooler than what the camera is set at. We also have a bit of blue color in the shade side of the face. Once we put the gel on, and set the color temperature higher, not only do we create a more natural background and correct the subject shadow-balance, there is also the pleasing bonus of having a warmer hairlight from where the sunlight is hitting the subjects shoulder and head.
In my experience, I have found that a ¼ CTB is great for balancing with general overcast, which is around 6500-7000K. A ½ CTB will push you up to 7500-8000K which is great for light / medium shade. A Full CTB gel will balance in the deepest of shades.
The video shows a few more examples of how to use this, both for correction and effect. The current technology of our field has made it easier than ever to venture away from the controlled studio, and techniques such as balancing with various ambient temperatures are increasingly useful.