Find a Neutral Using Photoshop CS5 Curves Panel
Using the Curves panel in Photoshop Creative Suites 5, you can fix images created in less-than-perfect lighting. The final part of creating a tone curve is Finding a Neutral. This step applies only if you’re working on a color image. Be sure to find and set the highlight and shadow values and adjust the midtones before proceeding to find the neutral.
The key to understanding color is knowing that equal amounts of color create gray. By positioning the mouse cursor over gray areas in an image and reading the values in the Info panel, you can determine which colors you need to adjust.
With the Curves panel open, position it so that you can see the Info panel.
If the Info panel is buried under another panel or a dialog box, choose Window→Info to bring it to the front.
Position the cursor over an image and, in the Info panel, look for the RGB values in the upper left section.
You see color values and then forward slashes and more color values. The numbers before the slash indicate the values in the image before you opened the Curves panel; the numbers after the slash show the values now that you’ve made changes in the Curves panel. Pay attention to the values after the slashes.
Position the cursor over something gray in your image.
It can be a shadow on a white shirt, a countertop, a road — anything that’s a shade of gray. Look at the Info panel. If your image is perfectly color balanced, the RGB values following the forward slashes should all be the same.
If the color isn’t balanced, click the Set Gray Point eyedropper in the Curves panel and click the neutral or gray area of the image.
The middle eyedropper (Set Gray Point) is a handy way of bringing the location you click closer together in RGB values, thereby balancing the colors.
Curves can be as complex or as simple as you make them. As you gain more confidence in using them, you can check neutrals throughout an image to ensure that all unwanted color casts are eliminated. You can even individually adjust each color’s curve by selecting it from the Channel drop-down list in the Curves panel.
When you’re finished with color correction, using the Unsharp Mask filter on your image is a good idea.