The Levels command allows you to identify shadow and highlight points by using the dialog’s built-in histogram. The Input and Output sliders allow you to limit highlight and shadow percentages, and the Input Gamma slider allows you to adjust midtones in an image quickly and easily. The sliders also provide real-time feedback when the Preview option is enabled.
As you move the Input and Output level sliders, the values in the corresponding fields change. If you prefer, you can enter values in these fields, but moving the sliders is usually the quickest and easiest way to make an adjustment, especially with the real-time Preview option enabled.
Input Levels
Moving the Black and White input level sliders in toward the center of the histogram effectively stretches the range of the image. By moving the Black Point slider from its default position (zero) to the right, you are telling Photoshop to make all pixels from the new position and lower (those to the left) black. The same rule applies when moving the White Point slider from its default position (255) to the left. All pixels from the new position and higher (to the right of the slider) become white. Images that are lacking in contrast do not fill the entire tonal range of the histogram. But if you move the Black and White Point sliders in toward the center until they line up directly underneath the left and right ends of the histogram, you can stretch the dynamic range of the image, thereby increasing contrast and saturation.
The Gamma, or gray, slider allows you to lighten or darken the midtones in the image. The slider’s default position is at the 50% gray point (level 128). Moving it to the left lightens the midtones; moving it to the right darkens them.
Output Levels
Adjusting the Black and White output level sliders compresses the image rather than squeezes it. By moving the Black output slider to the right from its default position of zero, you are limiting the darkest pixels in the image and compressing the overall tonal range. The White output slider behaves in much the same way. By moving it to the left from its default position of 255, you are limiting the lightest pixels in the image. Unless you’re using extremely outdated printing methods, there’s no real reason to move these sliders from their default positions.
Levels and Color
When editing color images with Levels, you have the option of adjusting the composite channel (all colors) or individual channels. More often than not, you’ll be making a Levels adjustment to the composite channel (RGB, CMYK, or Lab). When you do, Photoshop applies the adjustment equally to all color channels in the image. On the right side of the Levels dialog box are three eyedroppers. The left eyedropper is for setting the black point, the middle for setting the neutral midpoint, and the right for setting the white point in the image. You can use these eyedroppers, along with the Levels dialog histogram, to color-correct an image with just a couple of clicks. They are especially helpful when attempting to remove a color cast. For many images, selecting the black and white point eyedroppers in the dialog and clicking in the image window can stretch the tonal range and help balance the image’s color—without even having to set a midpoint with the middle eyedropper. However, before clicking in the image, it helps to first identify the darkest and lightest areas. To identify a black, white, and gray point in the image, first change your Info palette to display grayscale values. Hover over the image and refer to the palette to find the approximate darkest and lightest areas. Proceed to click in these areas with the respective eyedroppers.
As you move the Input and Output level sliders, the values in the corresponding fields change. If you prefer, you can enter values in these fields, but moving the sliders is usually the quickest and easiest way to make an adjustment, especially with the real-time Preview option enabled.
Input Levels
Moving the Black and White input level sliders in toward the center of the histogram effectively stretches the range of the image. By moving the Black Point slider from its default position (zero) to the right, you are telling Photoshop to make all pixels from the new position and lower (those to the left) black. The same rule applies when moving the White Point slider from its default position (255) to the left. All pixels from the new position and higher (to the right of the slider) become white. Images that are lacking in contrast do not fill the entire tonal range of the histogram. But if you move the Black and White Point sliders in toward the center until they line up directly underneath the left and right ends of the histogram, you can stretch the dynamic range of the image, thereby increasing contrast and saturation.
The Gamma, or gray, slider allows you to lighten or darken the midtones in the image. The slider’s default position is at the 50% gray point (level 128). Moving it to the left lightens the midtones; moving it to the right darkens them.
Output Levels
Adjusting the Black and White output level sliders compresses the image rather than squeezes it. By moving the Black output slider to the right from its default position of zero, you are limiting the darkest pixels in the image and compressing the overall tonal range. The White output slider behaves in much the same way. By moving it to the left from its default position of 255, you are limiting the lightest pixels in the image. Unless you’re using extremely outdated printing methods, there’s no real reason to move these sliders from their default positions.
Levels and Color
When editing color images with Levels, you have the option of adjusting the composite channel (all colors) or individual channels. More often than not, you’ll be making a Levels adjustment to the composite channel (RGB, CMYK, or Lab). When you do, Photoshop applies the adjustment equally to all color channels in the image. On the right side of the Levels dialog box are three eyedroppers. The left eyedropper is for setting the black point, the middle for setting the neutral midpoint, and the right for setting the white point in the image. You can use these eyedroppers, along with the Levels dialog histogram, to color-correct an image with just a couple of clicks. They are especially helpful when attempting to remove a color cast. For many images, selecting the black and white point eyedroppers in the dialog and clicking in the image window can stretch the tonal range and help balance the image’s color—without even having to set a midpoint with the middle eyedropper. However, before clicking in the image, it helps to first identify the darkest and lightest areas. To identify a black, white, and gray point in the image, first change your Info palette to display grayscale values. Hover over the image and refer to the palette to find the approximate darkest and lightest areas. Proceed to click in these areas with the respective eyedroppers.
Levels
![Levels]()
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