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Measure Color

You'll need to measure the color of a photograph, especially when correcting skin tones.

Here are several ways to measure a color on your photograph.

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 Color Picker Tool & Info Panel

1) Make sure the Background copy layer is active (highlighted).

2) Select the Color Picker tool.

3) In options bar/Tool Options, set the sample size to Average (5 x 5).

Now, you're averaging the color of 5 pixels by 5 pixels, or 25 pixels total.

4) Open the Info panel in the panel bin, or go to Windows > Info.

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5) Move the Eyedropper cursor around the photograph.

The red (R), green (G), and blue (B) values change in the Info panel.

6) If you click, the color appears as the foreground color.

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Color Cast Determination

To determine the color of a color cast:

• Find an area on the photograph that should be gray.

If there's a color cast, this should-be gray area will be tinted with the color cast.

The should-be gray area must be located in the same light as the subject of the photograph.

You can also:

• Find an area that's white with detail.

Detail means the white area isn't overexposed.

For example, let's say you have a photograph taken in a loft.

The foreground, where a friend is sitting on a sofa, is too orange from the track lighting.

Your friend is orange because you forgot to switch your white balance to the tungsten setting (light bulb icon).

You have too choices of areas to measure the color:

1) He's wearing a white shirt.

The shirt is overexposed on the shoulders, but has some texture in front.

The RGB values of the overexposed area will be 255 in the Info panel.

2) In the dimly lighted background, there's a gray chair.

Don't measure the color on the gray chair.

It's not in the same light as your friend.

Don't measure the color on the overexposed portions of your friend's white shirt.

Do measure the color on the front of the shirt, where there's derail.

Skin Tone Correction

For a skin tone correction, place the Eyedropper cursor on a representative location on the subject's face, often on the forehead.

Make sure the area is:

• Without glare.

• Not in a shadow.

• An unblemished area.

• Without makeup other than a foundation, such as rouge on a cheek.

• Not being illuminated by light bouncing off of a colored hat or colorful clothing.

4) As you move the Eyedropper cursor around, the RGB values change in the Info panel.

Don't inadvertently click the mouse when using the Eyedropper tool.

The foreground color will change if you do so.

In the above photograph, the subject's forehead has the following color values:

R: 225

G: 187

B: 167

Find them in the Info panel below.

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Color Measured on Forehead

These RGB values are probably meaningless for color correction.

At first, it's hard to look at a skin tone, and be able to judge the color.

If you place the Eyedropper cursor on a neutral area in the photograph, the color cast will be more evident.

There's no optimum gray or white area in this photograph.

In the above photograph, the color in the lower-left corner was measured:

R: 212

G: 216

B: 227

Find them in the Info panel below.

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Color Measured on Lower-left Corner

The value for blue is ten to thirteen point higher than the values for the other two colors.

If the photograph had a neutral color balance, no color cast, then the values for the colors would be similar.

But, the blue value is high.

A high blue means the yellow is low.

Yellow needs to be added.

Gray Card & the

GretagMacBeth ColorChecker

Gray Card

If you're going to photograph someone, you could have the person hold up a gray card, for the first photograph.

Then, when need to measure the color to see if there's a color cast, you have a guaranteed should-be gray area in one of the photographs.

Make sure the card is in the same light as the subject, and if the lighting changes, photograph the gray card again.

Purchase a durable gray card, not some flimsy house brand.

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GretagMacBeth ColorChecker

You can include a GretagMacBeth ColorChecker card in one of the photographs.

The card has a range of tones from white to black, and a range of colors.

Later, when you're at your computer, you can use the photograph with the card to set the black, gray, and white, points.

You won't have to figure out where to click a photograph.

Just click three times on the appropriate squares on the card.

When photographing the card, make sure it's in the same light as the subject, and if the lighting changes, photograph the card again.

Don't confuse the GretagMacBeth ColorChecker with the GretagMacBeth ColorChecker SG, which is $280.

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More

• For more about choosing colors, go to Color Picking.

• The Curvemeister program has a distinctive way of depicting color called the Hue Clock.

The position of the clock hand, and length of the hand, shows the color.

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