Step 3: Find Darkest And Lightest Points

From our work in the prior step, we know that we have a color cast to remove. As the eagle's white feathers is the best place to check for and remove the color cast, place an eyedropper point on one of the feathers. Doing this allows you to continuously monitor the colors (or lack of color) in the white feathers as you do the editing.

■ To be precise when doing color corrections, you can do your work by the numbers by using the Color and Info palettes. If they are not showing, choose Window ^ Color and Window >- Info. I

suggest that you slowly drag the Info palette by the Info tab toward the bottom of the Color palette to combine them, as shown in Figure 8.5.

■ Choose View ^ Actual Pixels (Alt+Ctrl+0) to display the image at 100% so that picking the best white-point is easy. Press the Spacebar to get the Hand tool. Click and drag the image until the eagle's head is in full view.

■ Click the Eyedropper tool (I) in the Tools palette. Click inside the Sample Size box in the Options bar and choose 3 by 3 Average from the pop-up menu, which makes it easier to get a good reading with the eye-dropper tool.

■ Click and drag in the image across the white feathers. As you drag, watch the values in the RGB values in the Info palette and the foreground color in the Color palette. You'll notice that the blue values are usually higher than the red or green values indicating that we have a blue cast to remove.

■ To set a point, press Shift to switch temporarily from the Eyedropper tool to the Color Sampler tool and click in the image in the lightest area that you can find on the top of the eagle's head, as shown in Figure 8.6. Now look at the Info palette. You should now see a #1 point with values for R, G, and B. The point I picked directly above the eagle's eye shows red, green, and blue values of 181,204, and 235 respectively. Since this point is supposed to be white, all the color channel values should be close to equal. Yet there is a 54 point difference between the red and blue values — a definite blue colorcast for sure!

This point gives us a good white point to use to monitor colorcasts, but it may not be the brightest white, which we need to set accurate overall white and black points.

■ Choose View ^ Fit on Screen (Ctrl+0) so that you can see the entire image.

■ To find the lightest point in the image, choose Image ^ Adjustments ^ Threshold to get the Threshold dialog box shown in Figure 8.7. Click the slider and drag it all the way to the right and then slowly bring it back toward the left until you see a small amount of white in the image, as shown in Figure 8.8. The Threshold Level should be around 195 in the Threshold dialog box.

■ Press Shift and drag the cursor over the white area at the top of the image while watching the second number in the R, G, and B values in the Info palette. You'll notice that R, G, and B values

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have two numbers; the first, before Threshold, was applied and the second number is the value after Threshold is applied. So, when you have the cursor positioned over a point that shows 255,255, and 255, press Shift and click to set a point. Looking at the bottom of the Info palette you now see the values for the #2 point. ■ Now you must set the darkest point. To find it, click the slider in the Threshold dialog box and drag it all the way to the left and then slowly drag it to the right until you only see a small amount of black in the image, as shown in Figure 8.9. The Threshold Level in the Threshold dialog box should be around 10.

■ Press Shift and drag the cursor over the largest black area in the image while watching the R, G, and B values in the Info palette. When the second numbers following R, G, and B are 0, 0, and 0, click to set a third point. Looking at the bottom of the Info palette you now see the values for the #1, #2, and #3 points, as shown in Figure 8.10.

8.10

■ Click Cancel to close the Threshold box. You should once again see the eagle; only you now ought to see the three points that were just set. Each of them will be numbered.

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