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Need Accurate Color?: Let Grey Cards and White Balancing Come to Your Rescue!
The superheroes of accurate color have arrived!
Since it is imperative, then, for online retailers to represent the colors of their products accurately, it is good to know how to use two superheroes of accurate color—grey cards and white balance—to your advantage.
What is a Grey Card?
A grey card is designed to help photographers to adjust their exposure and white balance settings consistently by providing a reference point. This reference point will set a white balance, or color balance, point for a particular image set and all images captured thereafter.
The reference point will prompt your camera to compensate for any illuminant color in the space where you plan to shoot by adjusting the white balance and/or color profile.
How do I use a Grey Card?
To measure your reference point, place the grey card in the area or scene in which you intend to take a photograph with the grey side facing toward the camera. For the most accurate results, place the card directly where your subject might stand or rest so that it reflects the light source. Then, adjust your settings to ensure optimal exposure and focus and take a test shot. You might need to take two or three to get the image looking the way you would like.
Once you have captured the image in camera, you can then navigate to the camera’s internal shooting menu and select one of the preset white balance options or “custom white balance,” which are settings that all modern DSLRs come equipped with.
If you have time, it is a good practice to repeat this process several times to make sure that you have captured an accurate reference point before you begin shooting. If the light source, time of day, or location changes during your shooting session, then you will need to use the grey card to measure another reference point.
Why does the Grey Card work?
Essentially, the grey card works because of its lack of color. Grey is a neutral tone, and even though there are many different shades of grey, the grey used on a grey card is considered to be a “middle grey.” The middle grey hue makes it easy for the camera to understand a given lighting situation and prescribe the best solution.
It is quite easy to use a grey card. Simply place it in the area where you plan to shoot your subject, facing the direction of where you plan to place the camera. If you are using artificial light, you will want to make sure you light the grey card the same way you plan to light your subject. You should have a “custom white balance” selection in your camera menu. You will find this setting and select it and take a picture. It helps to do this process at least three times to make sure that the light is being registered correctly.
In AUTO shooting mode, the camera automatically searches for this medium grey hue in a scene in order to determine the right exposure and white balance, and this is also how the camera determines the correct white balance when you set white balance to AUTO.
By using a grey card, you are basically retaining more control over the final appearance of the image by adjusting white balance on your own.
A grey card works because of its lack of color and because it is a neutral tone.
Should I use a Grey Card or my camera’s white balance presets?
Both methods are effective means of achieving accurate color, as long as you know how to use them to your advantage. Modern DSLRs are equipped with a “grey card” system of their own. When you set your camera’s white balance to AUTO, your camera fishes around in a scene for medium grey and applies the appropriate white balance preset that will create color balance.
For example, if you were taking a photograph in a room with tungsten bulbs, your camera would add cooler, bluer tones to the image in order to create that neutral medium grey. Another example can be seen in the images below, which were captured in natural sunlight. Based on the differing color temperatures of the images, you can see that setting the proper white balance is important for capturing accurate colors:
In product photography, color temperature should be precise. For convenience and versatility, most photographers leave their white balance mode set to AUTO and allow the camera to interpret the light source. This usually produces great results!
Professional-grade DSLRs also come equipped with a Kelvin setting that allows you to change your white balance based off of the numbers on the Kelvin scale. For example, if you wanted to photograph something in daylight, you would need to set your camera to 5200k.
To use a grey card, simply place it in the shooting area facing the camera.
How Do I Correct White Balance in Photoshop?
While capturing accurate colors in camera will save you post-processing time, Photoshop is more than capable of helping you to correct colors that may not have translated well. The process is relatively simple. Open a test image that contains your grey card in Photoshop and create a Levels Adjustment Layer. You will find three eyedroppers stacked next to the Levels histogram. Select the middle eyedropper and click on the grey card. Photoshop will automatically adjust the image’s color levels for you. If you need to apply those settings to other images taken in the same lighting conditions, click the drop-down menu in the top-right corner of the Levels column and select “Save Levels Preset.” Name and save the preset and then open up your other file(s) for editing. For each image, find the “Load Levels Preset” from the Levels column’s drop-down menu and select your saved preset file to apply it.
To accomplish this in Lightroom, simply select the White Balance eyedropper tool in the Basic menu of the Develop Module and click on the grey card. Next, highlight all of the images that you want to color correct and click the “Sync” button in the lower right corner of the screen. Check “White Balance,” click “Synchronize,” and watch the magic unfold.
Now that you understand how to use a grey card and adjust your white balance settings, you should be able to produce great accurate colors in your product photos, even in quickly-changing lighting conditions. To ensure that you’re getting the best colors possible, it is recommended that you use artificial strobes in a stable lighting environment and lock your camera settings to ensure consistency from image to image in your inventory.
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