Here are some Photoshop-only features that are useful for color correction.
With Photoshop, but not Photoshop Elements, you can make a selection with Color Range.
Go to Select > Color Range.
Set the fuzziness from about 20 to 30.
Use the Eyedropper + tool, in the middle of the other Eyedropper tools.
With the Eyedropper + tool, as you click the areas that you want to correct, each new area is added to the selection.
Your selection appears in the preview window as a B&w image.
When finished, click OK, and the selection will appear on your photograph.
Then, use one of the color correction or skin tone correction tutorials.
With the Eyedropper tool, you can click multiple locations on a photograph, and the values of each sample appear and remain in the Info panel.
As you edit, you can watch as a selected shadow, midtone, highlight, and a fourth location, change, as before-and-after values are displayed.
Your using the RGB color space, in which the color information is divided into three channels, red, green, and blue.
There are several other color spaces, including CMYK and LAB.
In some color correction situations, there's an advantage to switch from the RGB color space to another color space.
The CMYK color space uses the subtractive colors, cyan, yellow, magenta, and key (black).
Black (K) is part of CMYK because of the its origin in the color printing industry.
Because mixing equal amounts of cyan, magenta, and yellow inks doesn't yield a satisfactory black, black ink is also used.
This also saves money.
When black ink is used, less of the more expensive colored inks is required.
Because we see skin tones as being yellow and magenta, rather than blue and green, skin tone correction discussion uses CMYK.
You can remain in the RGB color space, and can measure the CMYK values using the Eyedropper tool and the Info panel.
Go to Measure Color.
In the LAB color space, color is subdivided into three channels, just like the RGB color space.
The RGB color space has red, green, and blue, channels.
The luminosity (brightness) information is embedded with each color of the three colors.
In the LAB color space, luminosity is separated from the color information of hue and saturation.
|L Channel||a Channel||b Channel|
Here's more about each LAB channel.
The L channel, or Lightness channel, measures the luminosity.
The L-channel range is from 0, black, to 100, white.
The a channel measures the color between magenta and green, ranging from -128 to +128.
A value of 0 is neutral.
Negative values indicate green, while positive values indicate magenta.
The b channel measures the color between blue and yellow, ranging from -128 to +128.
A value of 0 is neutral.
Negative values indicate blue, while positive values indicate yellow.
When correcting skin tone, by separating the luminosity information from the color information, the color values remain more constant on a face with shadows.
The skin tone in a shadow will have similar color values to the skin tone in brighter lighting, with each having very different L values.
You can adjust yellow, magenta, and cyan, by percentage increases and decreases.
By changing the colors by a percentage, you can more easily apply the same correction to other photographs.
Go to Image > Adjust > Selective Color.