Should custom White Balance using a gray card be used every shoot? yes, for that we must use the 18% gray card. If we have determined the correct exposure, we can use it for every photo we take, as long as the light remains exactly the same. . This will ensure the image colors will be accurate to the lighting in the camera room or location. After each camera is white balanced, take an image of the gray card.
If you work in studio with or without help:
Please ensure the camera room is metered at least once a week and exposure and lighting is accurate.
Check and confirm all camera settings are correct. Ensure the camera is set to use Custom White Balance.
Fully unroll the white backdrop for testing (or any color background you’re using).
Take a posing stool or have someone hold the grey card and put it on the subject mark.
Set/hold the gray card on the stool against a wooden block approximately 36 inches off the floor. The card should lay as flat against the block as possible.
Turn the card 5 to 15 degrees towards the main light.
Set the focal length of the camera between 85mm and 100mm—Which ever can zoom in closes.
Take a photo of the gray card making sure there is NOTHING else in the shot. Only the card should be visible. If using a card without a target on it, the camera will not be able to focus; switch to manual focus and take the shot. It's okay if it is not sharp – that doesn't matter. The image should look like the one below. If anything other than gray is in the image – get closer!
Navigate through the camera menu to “Custom White Balance” It will then ask to choose an image.
Select the image of the gray card taken in step 8. The camera may prompt to “Use WB data from this image for custom WB” – select OK. Once the image is saved, the camera is ready for the first session!
