Before a photo shoot it is a good idea to set a “custom white balance”.
Our plan was to do portraits on the north side of a brick building which means no direct sunlight. The only light source would be the big blue northern sky which would tint Ava’s skin bluish.
First I photographed an 18% gray card (upper left) in the same spot Ava would be. As you can see it has a blue tint thanks to the blue sky. To show Ava what the blue sky would do to her face I took a picture of her (upper right). The bluish tint was obvious to her, even on the back of my camera.
I used the photo of the gray card to set a custom white balance. You can learn how at the links below. In essence I was telling the camera to change the white balance so the gray card would be a neutral gray. After I did that I photographed the gray card again and it now looks neutral gray just like it is supposed to look (lower left). Then I photographed Ava’s face and her skin now looks just like it is supposed to (lower right). Now every photo I take at that location (as long as the light doesn’t change) will have correct skin tones. That saves me the time of having to color correct every single photo after the fact.
Links
The “Custom White Balance” Series
Why and When To Set A Custom White Balance