Using a Gray card for better color rendition

If you've ever relied on your camera's white balancing functions, you know how they are supposed to work. They get you in the ballpark but still need some tweaking.  Getting accurate color balance with just about any camera can be easy with an 18% gray card.

A gray card is your friend

The term “white balance “ is a misnomer and needs further explanation. When looking for all-around color accuracy the best color to show balance is gray. Why? It is an average tone representing an approximate 18% coverage. White only tests (samples) for the upper or high end of the spectrum, as black indicates only the lower or darker end of the spectrum. When you use the White balance function your camera it looks to balance to a neutral gray area. The use of the gray card gives your camera a neutral reference point as a baseline for calculating all exposures from a given scene. If the scene or lighting changes, you will want to take another white balance reading.

Place the gray card on or as near the subject as possible so the light hitting the gray card is the same as the light hitting the subject. If shooting a portrait, have the subject hold the gray card in front of their face for a test shot. When you process your photos in Photoshop or your choice of image editing programs, open this test shot. Using your histogram adjustments, click on the middle (gray) eye-drop icon. Save this level adjustment setting, and then apply it to the other photos  taken under the same lighting conditions. The application of this adjustment will show the correct white balance adjustment.

Making a Gray Card

While you can buy an 18% gray card at most photography stores, you're basically buying a piece of gray board. The benefit of buying a card is that you know you're getting exactly 18% gray. You can print out a gray card from your computer. If you pick a middle-of-the-road gray and print it, you'll have a good start. You can tweak it later if needed by using the eyedropper tool to get close to an 18% gray in the info dialog.

If your printer has a color profile, you will want to switch to the correct profile before printing for more accurate results.