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How to do Color and Tonal Adjustments in Photoshop

Before making color and tonal adjustments

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The powerful tools in Photoshop and ImageReady can enhance, repair, and correct the color and tonality (lightness, darkness, and contrast) in an image. Here are some items to consider before making color and tonal adjustments.

  • Work with a monitor that's calibrated and profiled. For critical image editing, this is absolutely essential. Otherwise, the image you see on your monitor will look different when printed. For more information on keeping color consistent throughout your workflow,
  • Whenever you make a color or tonal adjustment to an image, some image information is discarded. It's best to be judicious regarding the amount of correction you apply to an image.
  • (Photoshop) For critical work and maximum preservation of image data, it's best if the image you work with is 16 bits per channel (16-bit image) rather than 8 bits per channel (8-bit image). As you make tonal and color adjustments and image data is discarded, the loss of image information is more critical in an 8-bit image than a 16-bit image. Photoshop CS has improved support for 16-bit images. Generally, 16-bit images have a larger file size than 8-bit images.

Note: If you jump back and forth between Photoshop and ImageReady, be aware that ImageReady converts 16-bit images to 8-bit for editing. Once the files are saved in ImageReady, they are permanently converted to 8-bit, and the discarded data is unrecoverable. However, if you are editing a 16-bit image in ImageReady and haven't saved it yet, you can return to Photoshop and the image will open as 16-bit without data loss.

  • Duplicate or make a copy of the image file. Working on a copy of your image preserves the original in the event you need to use the image in its original state.
  • Remove any flaws such as dust spots, blemishes, and scratches from the image before making color and tonal adjustments. For more information on retouching an image,
  • (Photoshop) Plan to use adjustment layers to adjust the tonal range and color balance of your image rather than applying an adjustment directly to the image layer itself. Adjustment layers let you go back and make successive tonal adjustments without discarding data from the image layer. Keep in mind that using adjustment layers adds to the file size of the image and demands more RAM from your computer. For more information on using adjustment layers,
  • (Photoshop) Open the Info or Histogram palette in Expanded view. As you evaluate and correct the image, both palettes display invaluable feedback on your adjustments. For more information on using the Info palette, and for more information on the Histogram palette,
  • You can make a selection or use a mask to confine your color and tonal adjustments to part of an image. Another method to selectively apply color and tonal adjustments is to set up your document with image components on different layers. Color and tonal adjustments are applied to only one layer at a time and will affect only the image components on the targeted layer

 

Basic steps for correcting images

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The following workflow overview is a starting point for correcting the tonality and color of an image.

Note: For some images, the use of the quick adjustment commands in Photoshop and ImageReady might give satisfactory results. For more information on the various Auto commands,

To make color and tonal adjustments:

  1. (Photoshop) Use the histogram to check the quality and tonal range of the image. For information on using the histogram,
  2. Adjust the color balance to remove unwanted color casts or to correct oversaturated or undersaturated colors.

    You can choose from the following color adjustment methods:

    (Photoshop) Auto Color command

    Quickly corrects the color balance in an image. Although its name implies an automatic adjustment, you can fine tune how the Auto Color command behaves. For more information,

    (Photoshop) Match Color command

    Matches the color from one photo to another photo, from one layer to another layer, and from a selection in an image to another selection in the same image or different image. This command also adjusts the luminance and color range and neutralizes color casts in an image. For more information,

    (Photoshop) Color Balance command

    Changes the overall mixture of colors in an image. For more information,

    Hue/Saturation command

    Adjusts the hue, saturation, and lightness values of the entire image or of individual color components. For more information on the Hue/Saturation command,

    (Photoshop) Replace Color command

    Replaces specified colors in an image with new color values. For more information on the Replace Color command,

    (Photoshop) Selective Color command

    Adjusts the amount of process colors in individual color components. For more information on the Selective Color command,

    (Photoshop) Channel Mixer command

    Modifies a color channel and makes color adjustments not easily done with other color adjustment tools. For more information on the Channel Mixer command,

    Levels command

    Adjusts color balance by setting the pixel distribution for individual color channels. For more information on the Levels command,

    (Photoshop) Curves command

    Provides up to 14 controls points for highlight, midtone, and shadow adjustments for individual channels. For more information on the Curves command,

    Photo Filter command

    Makes color adjustments by simulating the effects of photographing with a Kodak Wratten filter in front of a camera lens. For more information on the Photo Filter command,

  3. Adjust the tonal range.

    Begin tonal corrections by adjusting the values of the extreme highlight and shadow pixels in the image, setting an overall tonal range for the image. This process is known as setting the highlights and shadows or setting the white and black points.

    Setting the highlights and shadows typically redistributes the midtone pixels appropriately. However, you may need to adjust your midtones manually.

    There are several different ways to set an image's tonal range:

    • You can drag sliders along the histogram in the Levels dialog box. For more information using the sliders in Levels,
    • (Photoshop) You can adjust the shape of the graph in the Curves dialog box. This method lets you adjust any point along a 0-255 tonal scale and provides the greatest control over an image's tonal quality. For more information on using the Curves command,
    • (Photoshop) You can assign target values to the highlight and shadow pixels using either the Levels or Curves dialog box. This can help preserve important highlight and shadow details in images being sent to a printing press or laser printer. You might also need to tweak the target values after sharpening. For more information on setting target values,
    • Adjust the tonality in the shadow and highlight areas using the Shadow/Highlight command. This adjustment is especially useful to correct photos, where the subject is silhouetted due to strong backlighting or where the subject is a bit light from being too close to the camera flash. For more information on the Shadow/Highlight command,
  4. (Optional) Make other special color adjustments.

    Once you have corrected the overall color balance of your image, you can make optional adjustments to enhance colors or produce special effects. For more information on special color effects,

  5. Sharpen the edges of the image.

    As one of the final steps, use the Unsharp Mask filter to sharpen the clarity of edges in the image. The amount of sharpening required for an image varies due to differences in quality produced by different digital cameras and scanners. For more information on sharpening images,

  6. (Photoshop) Use the Output sliders in the Levels dialog box or the Curves dialog box to bring important details in the highlights and shadows into the gamut of an output device, like a desktop printer. Do this if your image is being sent out to a printing press and you know the characteristics of the press.

    Because sharpening increases the contrast of neighboring pixels, it's possible that some pixels in critical areas might become unprintable on the press that you're sending your images to. This is why it's best to tweak the output settings after sharpening. For more information on adjusting the output settings,

 

Using a histogram to view the tonal range of an image (Photoshop)

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A histogram illustrates how pixels in an image are distributed by graphing the number of pixels at each color intensity level. This can show you whether the image contains enough detail in the shadows (shown in the left part of the histogram), midtones (shown in the middle), and highlights (shown in the right part) to make a good correction.


Using the color adjustment tools

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All Photoshop and ImageReady color adjustment tools work essentially the same way: by mapping an existing range of pixel values to a new range of values. The difference between the tools is the amount of control they provide. For an overview summary of the color adjustment tools,

 

Comparing corrections in CMYK and RGB (Photoshop)

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Even though you can perform all color and tonal corrections in RGB mode and nearly all adjustments in CMYK, you should choose a mode carefully. Whenever possible, avoid multiple conversions between modes, because color values are rounded and lost with each conversion. If an RGB image is to be used on-screen, you needn't convert it to CMYK mode. Conversely, if a CMYK scan is to be separated and printed, you needn't perform corrections in RGB mode.

If you must convert your image from one mode to another, it makes sense to perform most of your tonal and color corrections in RGB mode and use CMYK mode for fine-tuning. Advantages of working in RGB mode include the following:

  • You can save memory and improve performance because you are working with fewer channels.
  • The range of colors in RGB spaces is much larger than that of CMYK spaces, so more colors are likely to be preserved after adjustments. For more information,

Using the Proof Setup and Proof Color commands, you can preview composite CMYK colors and separation plates using the CMYK working space defined in the Color Settings dialog box. Or, you can preview colors using a custom CMYK color profile.

You can edit an image in RGB mode in one window and view the same image in CMYK colors in another window. Choose Window > Arrange > New Window for (file name) to open a second window with the image you're working on. Make sure Working CMYK is chosen for Proof Setup and then use the Proof Color command to turn on the CMYK preview in one of the windows

 

Identifying out-of-gamut colors (Photoshop)

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A gamut is the range of colors that a color system can display or print. A color that can be displayed in RGB may be out of gamut, and therefore unprintable, for your CMYK setting.

Photoshop automatically brings all colors into gamut when you convert an RGB image to CMYK. But you might want to identify the out-of-gamut colors in an image or correct them manually before converting to CMYK.

In RGB mode, you can identify out-of-gamut colors in the following ways:

    • In the Info palette, an exclamation point appears next to the CMYK values whenever you move the pointer over an out-of-gamut color.
    • In both the Color Picker and the Color palette, an alert triangle appears and the closest CMYK equivalent is displayed whenever you select an out-of-gamut color. To select the CMYK equivalent, click the triangle or the color patch.
    • Use the Gamut Warning command.

To turn on or off the highlighting of out-of-gamut colors:

  1. Choose View > Proof Setup, and choose the proof profile on which you want to base the gamut warning.
  2. Choose View > Gamut Warning. All pixels outside the gamut of the current proof profile space are highlighted.

To change the gamut warning color:

  1. Do one of the following:
    • In Windows, choose Edit > Preferences > Transparency & Gamut.
    • In Mac OS, choose Photoshop > Preferences > Transparency & Gamut.
  2. Under Gamut Warning, click the color box to display the Color Picker. Then choose a new warning color, and click OK. For best results, use a color that is not already present in the image.
  3. Enter a value in the Opacity text box. Values can range from 0 to 100%. Use this setting to reveal more or less of the underlying image through the warning color. Then click OK.
    Original image, and preview of out-of-gamut colors with green chosen for the gamut warning color

 

Using the Levels dialog box

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The Levels dialog box lets you correct the tonal range and color balance of an image by adjusting intensity levels of the image's shadows, midtones, and highlights. The Levels histogram serves as a visual guide for adjusting the image's key tones. For more information on how to read a histogram,

Settings made in the Levels dialog box can be saved for use on another image.

    Levels dialog box A. Apply Auto Color Correction B. Open Auto Color Correction Options dialog box C. Shadows D. Midtones E. Highlights
 
Using the Curves dialog box (Photoshop)

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Like the Levels dialog box, the Curves dialog box lets you adjust the entire tonal range of an image. But instead of using only three adjustments (white point, black point, gamma), with Curves you can adjust up to 14 different points throughout an image's tonal range (from shadows to highlights). You can also use Curves to make precise adjustments to individual color channels in an image. Settings made in the Curves dialog box can be saved for use on another image.

    Curves dialog box A. Highlights B. Midtones C. Shadows D. Adjust curve by adding points E. Draw a curve with the pencil F. Set black point G. Set gray point H. Set white point


 

Using the eyedropper tools in the Levels or Curves dialog box

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Both the Levels (both Photoshop and ImageReady) and Curves (Photoshop) dialog boxes have eyedropper tools for setting the black point, setting the white point, and adjusting the color balance of an image. Simultaneously, using an eyedropper tool also applies a tonal correction to all the pixels in an image.

Note: The Set Gray Point Eyedropper tool is used primarily for color correction and is unavailable when working with grayscale images.

For the best results, don't use the eyedropper tools in images that require a huge adjustment to map a pixel to the maximum highlight or minimum shadow values. Because the eyedropper tools shift the tonal value of all pixels in an image in equal amounts higher or lower, some pixels may get clipped. It's best to make only small adjustments with the eyedropper tools.

Important: Using the eyedropper tools will undo any previous adjustment you've made in Levels or Curves (Photoshop). If you plan to use the eyedropper tools, it's best to use them first, and then tweak your adjustments with the Levels sliders or Curves points (Photoshop).

 

Setting highlight and shadow target values (Photoshop)

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Assigning (targeting) an image's highlight and shadow values is necessary because most output devices (usually printing presses) cannot print detail in the blackest shadow values (near level 0) nor the whitest highlight values (near level 255). Specifying the minimum shadow level and maximum highlight level helps to bring the important shadow and highlight details within the gamut of the output device. For more information about the gamut of a device,

If you are printing an image on a desktop printer and your system is color managed, it's unnecessary to set the highlight and target values. The Photoshop color management system automatically makes adjustments to the image you see on the screen so it prints properly on your profiled desktop printer. For more information on producing consistent color from image editing to printing,

    Note: You can do the following procedure in the Levels dialog box in ImageReady.

To use target values to set highlights and shadows:

  1. Select the Eyedropper tool . You can choose 3 by 3 Average from the Sample Size menu in the Eyedropper tool options. This ensures a representative sample of an area rather than the value of a single screen pixel.
  2. Open the Levels or Curves dialog box.

    When you open Levels or Curves, the Eyedropper tool  is active outside the dialog box. You still have access to the scroll controls, the Hand tool , and the Zoom tool  using keyboard shortcuts.

  3. Do one of the following to identify areas of highlights and shadows that you want to preserve in the image:
    • Move the pointer around the image, and look at the Info palette to find the lightest and darkest areas that you want preserved (not clipped to pure black or white).
    • Drag the pointer in the image, and look at the Curves dialog box to find the lightest and darkest points you want to preserve. This method does not work if the Curves dialog box is set to the CMYK composite channel.

    When identifying the lightest highlight details that you want targeted to a printable (lower) value, don't include specular highlights. Specular highlights such as the highlight glint in jewelry or a spot of glare are meant to be the brightest points in an image. It's usually desirable to let specular highlight pixels be clipped (pure white, no detail) so no ink is printed on the paper.

    You can also use the Threshold command to identify representative highlights and shadows before opening Levels or Curves.

  4. Do one of the following to assign highlight values to the lightest area of the image:
    • In Levels, move the Output Levels highlight slider to set the highest highlight value. As you move the slider, the highlight value displays in the Output Levels text box and you can see a preview in the document window. The Output Levels slider lowers the values of the highlight pixels. Don't use the Output Levels slider if your image has a specular highlight and you want it to be pure white (level 255).
    • Double-click the Set White Point Eyedropper tool  in the Levels or Curves dialog box to display the Color Picker. Enter the values you want to assign to the lightest area in the image, and click OK. Then click the highlight you identified in step 3.

    If you accidentally click the wrong highlight, hold down Alt (Windows) or Option (Mac OS), and click Reset in the Levels or Curves dialog box.

    • Click Options in the Levels or Curves dialog box. In the Auto Color Correction Options dialog box, click the Highlights color swatch to display the Color Picker. Enter the values you want to assign to the lightest area in the image, and click OK.

    Depending on the output device, when you are printing on white paper, you can achieve a good highlight in an average-key image using CMYK values of 5, 3, 3, and 0, respectively. An approximate RGB equivalent is 244, 244, 244, and an approximate grayscale equivalent is a 4% dot. You can approximate these target values quickly by entering 96 in the Brightness (B) text box under the HSB area of the Color Picker.

    With a low-key image, you might want to set the highlight to a lower value to avoid too much contrast. Experiment with Brightness values between 96 and 80.

    Using the Eyedropper tool or the Auto Color Correction Options, you can adjust the pixel values throughout the image proportionately to the new highlight values. Any pixels lighter than the area you clicked are clipped (adjusted to level 255, pure white). The Info palette shows the values both before and after the color adjustment.

    Setting the target value for the Set White Point Eyedropper tool and then clicking a highlight to assign it the target value
  5. Do one of the following to assign shadow values to the darkest area of the image that you want preserved:
    • In Levels, move the Output Levels shadow slider to set the lowest shadow value.
    • Double-click the Set Black Point Eyedropper tool in the Levels or Curves dialog box to display the Color Picker. Enter the values you want to assign to the darkest area in the image, and click OK. Then click the shadow you identified in step 3.
    • Click Options in the Levels or Curves dialog box. In the Auto Color Correction Options dialog box, click the Shadows color swatch to display the Color Picker. Enter the values you want to assign to the darkest area in the image, and click OK.

    In most situations when you're printing on white paper, you can achieve a good shadow in an average-key image using CMYK values of 65, 53, 51, and 95. An approximate RGB equivalent is 10, 10, 10, and an approximate grayscale equivalent is a 96% dot.You can approximate these same values quickly by entering 4 in the Brightness (B) text box under the HSB area of the Color Picker.

    With a high-key image, you might want to set the shadow to a higher value to maintain detail in the highlights. Experiment with Brightness values between 4 and 20.

To use Threshold mode to identify the lightest and darkest areas in an image:

  1. Open the Levels dialog box, and make sure the Preview option is selected.

    Note: The Threshold mode in Levels is not available for CMYK images.

  2. Hold down Alt (Windows) or Option (Mac OS), and drag the white or black Input Levels triangle.

    The image changes to Threshold mode, and a high-contrast preview image appears. The visible areas of the image indicate the lightest parts of the image if you are dragging the white slider, and the darkest parts if you are dragging the black slider. If a color channel is selected in the Levels dialog box, the black area indicates where none of the given color component exists.

    Image preview in Threshold mode
  3. Slowly drag the slider to the center of the histogram to identify areas in the image that are being clipped (completely black or completely white). Use the pixels in these areas for targeting the black point and white point in your image.

 

Adjusting the gamma value of an image (ImageReady)

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In very simplistic terms, gamma is the measure of the contrast--brightness of the midtone values--produced by a device (like a computer monitor) or in a photographic image. A higher gamma value yields an overall darker image. Windows systems use a higher gamma value (usually 2.2) than Mac OS systems (usually 1.8), with the result that the same image is noticeably darker on a Windows system than on a Mac OS system.

Designers, particularly those who use Mac OS systems to create images that will be viewed on Windows systems, must consider the issue of cross-platform gamma. You can modify the gamma value of an image to compensate for the differences between Windows and Mac OS monitors.

The Gamma command modifies the pixel values in an image. By contrast, the Preview commands adjust the appearance of the image on your monitor but do not change the image's pixel values.

To preview an image using different gamma values:

    Choose View > Preview, and then choose one of the following:

    • Uncompensated Color to view the image with the monitor gamma uncorrected
    • Standard Macintosh Color to view the image with a gamma value of 1.8
    • Standard Windows Color to the image with a gamma value of 2.2
    • Use Embedded Color Profile to view the image using the embedded profile

    You can edit your image in one window and view the same image with a different gamma value in a second window. Choose Window > Arrange > New Window for (file name). With the new window active, choose View > Preview, and then choose a different gamma than the one used in the first window.

To adjust the gamma value automatically:

  1. Choose Image > Adjustments > Gamma.
  2. Select Preview to preview the adjustment in the image.
  3. Adjust the gamma:
    • Select Windows to Macintosh to adjust gamma for display in Mac OS.
    • Select Macintosh to Windows to adjust gamma for display in Windows.

    Note: Images created in Photoshop 4.0 or earlier use the Mac OS gamma value (1.8) by default and should be adjusted for display in Windows (unless gamma was adjusted when the image was created). Images created in Photoshop 5.0 or later use the Windows gamma value (2.2) by default and will be at the correct gamma for display in Windows with no adjustment.

To adjust the gamma value manually:

  1. Choose Image > Adjustments > Gamma.
  2. Select Preview to preview the adjustment in the image.
  3. Drag the Gamma slider, or enter a value in the text box between 0.1 and 9.99. The Gamma slider measures the amount of change from the current gamma value. (The slider does not indicate the actual gamma value.)

 

Using the Color Balance command (Photoshop)

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The Color Balance command changes the overall mixture of colors in an image for generalized color correction.

    Original image with greenish cast, and magenta/green level adjusted in midtones

To use the Color Balance command:

  1. Make sure the composite channel is selected in the Channels palette. This command is available only when you're viewing the composite channel.
  2. Do one of the following:
    • Choose Image > Adjustments > Color Balance.
    • Choose Layer > New Adjustment Layer > Color Balance. Click OK in the New Layer dialog box.
  3. Select Shadows, Midtones, or Highlights to select the tonal range on which you want to focus the changes.
  4. Select Preserve Luminosity to prevent changing the luminosity values in the image while changing the color. This option maintains the tonal balance in the image.
  5. Drag a slider toward a color you want to increase in the image; drag a slider away from a color you want to decrease in the image.

    The values above the color bars show the color changes for the red, green, and blue channels. (For Lab images, the values are for the a and b channels.) Values can range from -100 to +100.

 

Using the Hue/Saturation command

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The Hue/Saturation command lets you adjust the hue, saturation, and brightness of a specific color component in an image or simultaneously adjust all the colors in an image. In Photoshop, this command is especially good for tweaking specific colors in a CMYK image so they are within the gamut of an output device. For more information about the hue, saturation, and brightness (HSB) color model,.

Settings in the Hue/Saturation dialog box can be saved and loaded for reuse on other images. For more information,

To use the Hue/Saturation command:

  1. Do one of the following:
    • Choose Image > Adjustments > Hue/Saturation.
    • (Photoshop) Choose Layer > New Adjustment Layer > Hue/Saturation. Click OK in the New Layer dialog box.

    The two color bars in the dialog box represent the colors in their order on the color wheel. The upper color bar shows the color before the adjustment; the lower bar shows how the adjustment affects all of the hues at full saturation.

  2. (Photoshop) Choose which colors to adjust using the Edit pop-up menu:
    • Choose Master to adjust all colors at once.
    • Choose one of the other preset color ranges listed for the color you want to adjust.
  3. For Hue, enter a value or drag the slider until the colors appear as you want.

    The values displayed in the text box reflect the number of degrees of rotation around the wheel from the pixel's original color. A positive value indicates clockwise rotation, a negative value counterclockwise rotation. Values can range from -180 to +180.

    Color wheel and radius of color wheel A. Saturation B. Hue
  4. For Saturation, enter a value or drag the slider to the right to increase the saturation or to the left to decrease it.

    The color shifts away from or toward the center of the wheel, relative to the beginning color values of the selected pixels. Values can range from -100 (percentage of desaturation, duller colors) to +100 (percentage of saturation increase).

  5. For Lightness, enter a value or drag the slider to the right to increase the lightness (add white to a color) or to the left to decrease it (add black to a color). Values can range from -100 (percentage of black) to +100 (percentage of white).

    Note: Click the Reset button to undo a setting in the Hue/Saturation dialog box. Press the Alt (Windows) or Option (Mac OS) key to change the Cancel button to Reset.

To specify or modify the range of colors being adjusted in the Hue/Saturation command (Photoshop):

  1. Do one of the following:
    • Choose Image > Adjustments > Hue/Saturation.
    • (Photoshop) Choose Layer > New Adjustment Layer > Hue/Saturation. Click OK in the New Layer dialog box.
  2. In the Hue/Saturation dialog box, choose an individual color from the Edit menu.

    Four color wheel values (in degrees) display in the dialog box. They correspond to the adjustment sliders that appear between the color bars. The two inner vertical sliders define the color range. The two outer triangle sliders show where the adjustments on a color range "fall-off" (a feathering or tapering of the adjustments instead of a sharply defined on/off application of the adjustments).

  3. Use either the eyedropper tools or the adjustment sliders to modify the range of colors.

    Click or drag in the image with the Eyedropper tool to select a color range. To expand the range of color, click or drag in the image with the Add to Sample Eyedropper tool . To reduce the range of color, click or drag in the image with the Subtract from Sample Eyedropper tool . While an eyedropper tool is selected, you can also press Shift to add to the range, or Alt (Windows) or Option (Mac OS) to subtract from it.

    Hue/Saturation adjustment slider A. Hue slider values B. Adjusts fall-off without affecting range C. Adjusts range without affecting fall-off D. Moves entire slider E. Adjusts range of color component

    Or, do any of the following to the adjustment sliders:

    • Drag one of the white triangle sliders to adjust the amount of color fall-off (feathering of adjustment) without affecting the range.
    • Drag the area between the triangle and the vertical bar to adjust the range without affecting the amount of fall-off.
    • Drag the center area to move the entire adjustment slider (which includes the triangles and vertical bars) to select a different color area.
    • Drag one of the vertical white bars to adjust the range of the color component. Moving a vertical bar out from the center of the adjustment slider and closer to a triangle increases the color range and decreases the fall-off. Moving a vertical bar closer to the center of the adjustment slider and away from a triangle decreases the color range and increases the fall-off.
    • Ctrl-drag (Windows) or Command-drag (Mac OS) the color bar so that a different color is in the center of the bar.

    If you modify the adjustment slider so that it falls into a different color range, the name in the Edit menu changes to reflect this. For example, if you choose Yellow and alter its range so that it falls in the red part of the color bar, the name changes to Red 2. You can convert up to six of the individual color ranges to varieties of the same color range (for example, Red through Red 6).

    Note: By default, the range of color selected when you choose a color component is 30 wide, with 30 of fall-off on either side. Setting the fall-off too low can produce banding in the image.

To colorize a grayscale image or create a monotone effect:

  1. (Photoshop) If you are colorizing a grayscale image, choose Image > Mode > RGB Color to convert the image to RGB.
  2. Do one of the following to open the Hue/Saturation dialog box:
    • Choose Image > Adjustments > Hue/Saturation.
    • (Photoshop) Choose Layer > New Adjustment Layer > Hue/Saturation. Click OK in the New Layer dialog box.
  3. Select the Colorize option. If the foreground color is black or white, the image is converted to a red hue (0). If the foreground color is not black or white, the image is converted to the hue of the current foreground color. The lightness value of each pixel does not change.
  4. Use the Hue slider to select a new color if desired. Use the Saturation and Lightness sliders to adjust the saturation and lightness of the pixels.
 
Using the Photo Filter command (Photoshop)

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The Photo Filter command mimics the technique of putting a colored filter in front of the camera lens to adjust the color balance and color temperature of the light transmitted through the lens and exposing the film. The Photo Filter command also lets you choose a color preset to apply a hue adjustment to an image. If you want to apply a custom color adjustment, the Photo Filter command lets you specify a color using the Adobe Color Picker.

    Original image, and Warming Filter (81) with 60% Density applied

To change the color balance using the Photo Filter command:

  1. Do one of the following:
    • Choose Image > Adjustments > Photo Filter.
    • Choose Layer > New Adjustment Layer > Photo Filter. Click OK in the New Layer dialog box.
  2. To choose the filter color, do one of the following in the Photo Filter dialog box:
    • Select the Filter option and choose one of the following presets from the Filter menu:

    Warming Filter (85) and Cooling Filter (80)

    Are color conversion filters that tune the white balance in an image. If an image was photographed with a lower color temperature of light (yellowish), the Cooling Filter (80) makes the image colors bluer to compensate for the lower color temperature of the ambient light. Conversely, if the photo was taken with a higher color temperature of light (bluish), the Warming Filter (85) makes the image colors warmer to compensate for the higher color temperature of the ambient light.

    Warming Filter (81) and Cooling Filter (82)

    Are light balancing filters for minor adjustments in the color quality of an image. The Warming Filter (81) makes the image warmer (yellower), and the Cooling Filter (82) makes the image cooler (bluer).

    Individual Colors

    Apply a hue adjustment to the image depending on the color preset you choose. Your choice of color depends on how you're using the Photo Filter command. If your photo has a color cast, you can choose a complement color to neutralize the color cast. You can also apply colors for special color effects or enhancements. For example, the Underwater color simulates the greenish-blue color cast caused when photographing underwater.

    • Select the Color option, click the color square, and use the Adobe Color Picker to specify a color for a custom color filter. You can click the New Swatch button to save your custom color in the Swatches palette for future use.

    Make sure Preview is selected to view the results of using a color filter.

    If you don't want the image darkened by adding the color filter, be sure that the Preserve Luminosity option is selected.

  3. To adjust the amount of color applied to the image, use the Density slider or enter a percentage in the Density text box. A higher Density applies a stronger color adjustment.
  4. Click OK.

 

Using the Shadow/Highlight command (Photoshop)

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The Shadow/Highlight command is suitable for correcting photos with silhouetted images due to strong backlighting or correcting subjects that have been slightly washed out because they were too close to the camera flash. The adjustment is also useful for brightening up areas of shadow in an otherwise well-lit image. The Shadow/Highlight command does not just lighten or darken an image, it lightens or darkens based on the surrounding pixels (local neighborhood) in the shadows or highlights. This enables separate controls of the shadows and the highlights. The defaults are set to fix images suffering from backlighting problems. The Shadow/Highlight command also has a Midtone Contrast slider, Black Clip option, and White Clip option for adjusting the overall contrast of the image.

    Original image, and Shadow/Highlight Correction applied

To adjust the shadows and highlights in an image:

  1. Choose Image > Adjustments > Shadow/Highlight.

    Make sure the Preview option is selected in the dialog box if you want the image to update as you make adjustments.

  2. Adjust the amount of lighting correction by moving the Amount slider or entering a value in the percentage text box for Shadows or Highlights. Larger values provide either greater lightening of shadows or greater darkening of highlights. You can make adjustments to both Shadows and Highlights in an image.
  3. For finer control, select Show More Options to make the additional shadow or highlight adjustments:

    Tonal Width

    Controls the range of tones in the shadows or highlights that are modified. Move the slider to the left or right to decrease or increase the Tonal Width value. Smaller values restrict the adjustments to only the darker regions for Shadow correction and only the lighter regions for Highlight correction. Larger values include more tonal regions (such as adding the midtones) that are being adjusted. A value of 100% produces a linear effect; for Shadow correction, deep shadows get modified the most with no correction to bright highlights and half the shadow correction to midtones. The tonal width requirements will vary from image to image. Specifying a value that is too large for a given image might introduce halos around strong dark to light edges. The default settings attempt to reduce these artifacts. These halos may occur when the Shadow or Highlight Amount values are too large; they can also be reduced by decreasing these values.

    The Tone Width default is set to 50%. If you find that you are trying to lighten a dark subject but the midtones or lighter regions are changing too much, try reducing the Shadow Tone Width towards zero. Then only the darkest regions will be lightened. On the other hand, if you need to brighten up the midtones as well as the shadows, increase the Shadows Tone Width toward 100%.

    Radius

    Controls the size of the local neighborhood around each pixel that is used to determine whether a pixel is in the shadows or highlights. Moving the slider to the left specifies a smaller area, and moving it to the right specifies a larger area. The optimum local neighborhood size depends on the image. It's best to experiment with the adjustment. If the Radius is too large, the adjustment tends to brighten (or darken) the whole image rather than brightening the subject only. It's best to set the radius to be roughly the size of the subjects of interest in the image. Experiment with different Radius settings to obtain the best balance between subject contrast and differential brightening (or darkening) of the subject compared to the background.

  4. In the Adjustments area, do one of the following to apply an image adjustment:

    Color Correction

    Allows fine tuning of the colors in regions of the image that have changed. This adjustment is only available in color images. For example, if you increase the Shadows Amount slider, you will bring out colors that were dark in the original image. You may want these colors to be more or less vivid. Adjust the Color Correction slider to give the best results. In general, increasing values tend to produce more saturated colors and decreasing values produce less saturated colors.

    Note: Since the Color Correction slider only affects changed portions of the image, the amount of color variation depends on how much or little Shadows or Highlights Amount is applied. The greater the correction made to the shadows and highlights, the greater the range of color correction available. The Color Correction slider applies subtle control over the darkened or lightened colors in the image. If you want to change the color hues or saturation over the whole image, use the Hue/Saturation command after applying the Shadow/Highlight command.

    Brightness

    Adjusts the brightness in a grayscale image. This adjustment is only available for grayscale images. Moving the Brightness slider to the left darkens a grayscale image, and moving the slider to the right lightens a grayscale image.

    Midtone Contrast

    Adjusts the contrast in the midtones. Move the slider to the left to reduce the contrast and to the right to increase the contrast. You can also enter a value in the Midtone Contrast text box. A negative value reduces contrast, and a positive value increases contrast. An increase in Midtone Contrast adjustment produces greater contrast in the midtones while tending to darken the shadows and lighten the highlights.

    Black Clip and White Clip

    Specifies how much of the shadows and highlights will be clipped to the new extreme shadow (level 0) and highlight (level 255) colors in the image. Larger values produce an image with greater contrast. Be careful of setting the clipping values too large, as this will lead to reduced detail in the shadows or highlights as the intensity values get clipped and sent to pure black or white.

  5. Click the Save As Defaults button to save and make your current settings the Shadow/Highlights command defaults. To restore the original defaults, hold the Shift key down while clicking the Save As Defaults button.

    Note: Different Shadow/Highlight settings can be reused by clicking the Save button to save the current settings to a file and later using the Load button to reload the settings. For more information on saving and loading settings,

  6. Click OK.
 
Using the Match Color command (Photoshop)

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The Match Color command matches colors between multiple images, between multiple layers, or between multiple color selections. It also lets you adjust the colors in an image by changing the luminance, the color range, and neutralize a color cast. The Match Color command only works in RGB mode.

When you're using the Match Color command, the pointer becomes the Eyedropper tool . Use the Eyedropper tool on the image while making adjustments to view the color pixel values in the Info palette. This gives you feedback regarding the changes in color values as you use the Match Color command. For more information about using color samplers,

 

Using the Replace Color command (Photoshop)

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The Replace Color command lets you create a mask to select specific colors in an image and then replace those colors. You can set the hue, saturation, and lightness of the selected areas. Or, you can use the Color Picker to select the replacement color. The mask created by the Replace Color command is temporary.

    Making a selection and then transforming the color of the selection

To use the Replace Color command:

  1. Choose Image > Adjustments > Replace Color.
  2. Select a display option:
    • Selection to display the mask in the preview box. Masked areas are black, and unmasked areas are white. Partially masked areas (areas covered with a semitransparent mask) appear as varying levels of gray according to their opacity. For more information,
    • Image to display the image in the preview box. This option is useful when you are working with a magnified image or have limited screen space.
  3. To select the areas exposed by the mask, do one of the following:
    • Use the Eyedropper tool to click in the image or in the preview box to select the areas exposed by the mask. Shift-click or use the Add to Sample Eyedropper tool  to add areas; Alt-click (Windows), Option-click (Mac OS), or use the Subtract from Sample Eyedropper tool  to remove areas.
    • Double-click the Selection swatch. Use the Color Picker to target a color to be replaced. As you select a color in the Color Picker, the mask in the preview box updates.
  4. Adjust the tolerance of the mask by dragging the Fuzziness slider or entering a value. This controls the degree to which related colors are included in the selection.
  5. To change the color of the selected areas, do one of the following:
    • Drag the Hue, Saturation, and Lightness sliders (or enter values in the text boxes).
    • Double-click the Result swatch and use the Color Picker to select the replacement color.

    You can also save the settings you make in the Replace Color dialog box for reuse on other images. For more information on saving and loading settings,

 

Mixing color channels (Photoshop)

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The Channel Mixer command lets you create high-quality grayscale images by choosing the percentage contribution from each color channel. You can also create high-quality sepia-tone or other tinted images. Using the Channel Mixer, you can also make creative color adjustments not easily done with other color adjustment tools.

The Channel Mixer modifies a targeted (output) color channel using a mix of the existing (source) color channels in the image. Color channels are grayscale images representing the tonal values of the color components in an image (RGB or CMYK). With the Channel Mixer, you are adding or subtracting grayscale data from a source channel to the targeted channel. You are not adding or subtracting colors to a specific color component as you do with the Selective Color command. For more information about channels, and for more information about the Selective Color command,

To create monochrome images from RGB or CMYK images:

  1. In the Channels palette, select the composite color channel.
  2. Do one of the following to open the Channel Mixer dialog box:
    • Choose Image > Adjustments > Channel Mixer.
    • Choose Layer > New Adjustment Layer > Channel Mixer. Click OK in the New Layer dialog box.
  3. Select the Monochrome option to set Gray as the output channel. This creates a color image that contains only gray values.
  4. Use the Source Channels sliders to control the amount of detail and contrast in the images you plan to convert to grayscale.

    Before adjusting the percentages of the source channels, view how the each source channel affects the monochrome image. For example, in RGB, view the image with the Red channel set to +100% and the Green and Blue source channels set to 0%. Then, view the image with the Green source channel set to +100% and the other two channels set to 0%. Finally, view the image with Blue source channel set to +100% and the other channels set to 0%. In adjusting the percentages of the source channels, the best results are often when the combined values of the source channels add up to 100%.

  5. (Optional) If you select and then deselect the Monochrome option, you can modify the blend of each channel separately, creating a handtinted appearance.
    Handtinted effect by selecting (left)/deselecting (right) the Monochrome option
  6. (Optional) Drag the slider or enter a value for the Constant option. This option adjusts the grayscale value of the output channel. Negative values add more black, and positive values add more white. A -200% value makes the output channel completely black, and a +200% value makes the output channel completely white.

To mix color channels:

  1. In the Channels palette, select the composite color channel.
  2. Do one of the following to open the Channel Mixer dialog box:
    • Choose Image > Adjustments > Channel Mixer.
    • Choose Layer > New Adjustment Layer > Channel Mixer. Click OK in the New Layer dialog box.
  3. For Output Channel, choose the channel in which to blend one or more existing (source) channels. For more information,

    Choosing an output channel sets the source slider for that particular channel to 100% and all other channels to 0%. For example, choosing Red as the output channel sets the Source Channels sliders to 100% for Red, and 0% for Green and Blue (in an RGB image).

  4. Drag any source channel's slider to the left to decrease the channel's contribution to the output channel or to the right to increase it, or enter a value between -200% and +200% in the text box. Using a negative value inverts the source channel before adding it to the output channel.
  5. Drag the slider or enter a value for the Constant option. This option adjusts the grayscale value of the output channel. Negative values add more black, and positive values add more white. A -200% value makes the output channel completely black, and a +200% value makes the output channel completely white.

    You can also save the settings you make in the Channel Mixer dialog box for reuse on other images. For more information on saving and loading settings,

.

Using the Selective Color command (Photoshop)

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Selective color correction is a technique used by high-end scanners and separation programs to increase and decrease the amount of process colors in each of the additive and subtractive primary color components in an image. Even though Selective Color uses CMYK colors to correct an image, you can use it on RGB images as well as on images that will be printed.

    Selective color correction is based on a table that shows the amount of each process ink used to create each primary color. By increasing and decreasing the amount of a process ink in relation to the other process inks, you can modify the amount of a process color in any primary color selectively--without affecting the other primary colors. For example, you can use selective color correction to dramatically decrease the cyan in the green component of an image while leaving the cyan in the blue component unaltered.

To use the Selective Color command:

  1. Make sure the composite channel is selected in the Channels palette. The Selective Color command is available only when you're viewing the composite channel.
  2. Do one of the following:
    • Choose Image > Adjustments > Selective Color.
    • Choose Layer > New Adjustment Layer > Selective Color. Click OK in the New Layer dialog box.
  3. Choose the color you want to adjust from the Colors menu at the top of the dialog box. Color sets consist of the primary additive and subtractive colors plus whites, neutrals, and blacks.
  4. For Method, select an option:
    • Relative to change the existing amount of cyan, magenta, yellow, or black by its percentage of the total. For example, if you start with a pixel that is 50% magenta and add 10%, 5% is added to the magenta (10% of 50% = 5%) for a total of 55% magenta. (This option cannot adjust pure specular white, which contains no color components.)
    • Absolute to adjust the color in absolute values. For example, if you start with a pixel that is 50% magenta and add 10%, the magenta ink is set to a total of 60%.

    Note: The adjustment is based on how close a color is to one of the options in the Colors menu. For example, 50% magenta is midway between white and pure magenta and will receive a proportionate mix of corrections defined for the two colors.

  5. Drag the sliders to increase or decrease the components in the selected color.

    You can also save the settings you make in the Selective Color dialog box for reuse on other images. For more information on saving and loading settings,

 
Making quick overall adjustments to an image

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The Brightness/Contrast, Auto Levels, Auto Contrast, Auto Color (Photoshop), Variations, and Equalize (Photoshop) commands provide a quick and simple way to make overall adjustments to the color and tonality in an image. Since some of these adjustments features are automatic, keep in mind that you can always undo a command if you don't like the results.

    Auto adjustments A. Original image B. Auto Levels applied C. Auto Contrast applied D. Auto Color applied

 

Applying special color effects to images

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The Desaturate, Invert, Equalize (Photoshop), Threshold (Photoshop), and Posterize (Photoshop) commands change colors or brightness values in an image but are typically used for enhancing color and producing special effects, rather than for correcting color.

Special color effects A. Original B. Desaturate C. Invert D. Equalize E. Threshold F. Posterize G. Gradient Map

Note: You can also make color adjustments by blending colors from different channels.

 

Sharpening images

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When we view images, not only does our vision respond to color and tonality but also to the edges that define the shape of objects. Sharpening enhances the edge definition in an image. Whether your images come from a digital camera or a scanner, most images can benefit from sharpening. The degree of sharpening needed varies depending on the quality of the digital camera or scanner. Keep in mind that sharpening will not correct the problems of a severely blurred image.

 

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