Corel PHOTO-PAINT Help | Adjustment filters

Corel PHOTO-PAINT provides you with many filters to adjust the color and tone of images. Most of these filters are advanced tools that give you great control over the image correction process or let you change colors for specific effects.

The Adjustments docker lets you apply adjustment filters non-destructively as you view your changes in context. For more information, see Adjustments docker. In addition, you can apply adjustment filters non-destructively from the Effects docker. The Adjust menu also lets you access adjustment filters, but they can be applied only as destructive adjustments that permanently alter the image.

Many of these filters are also preset lens types. For more information about using lenses, see Lenses.

Auto-adjust

The Auto-adjust filter equalizes the shadows, midtones, and highlights in an image by automatically redistributing the significant pixel values throughout the tonal range. This adjustment is performed on each color channel of the image, resulting in changes to the color and tone of the image.

Original image (left); the image with Auto-adjust applied (right)

You can apply this adjustment non-destructively from the Histogram section of the Adjustments docker.

Contrast Enhancement

The Contrast Enhancement filter lets you adjust the tone, color, and contrast of an image while preserving shadow and highlight detail that is lost when you adjust the brightness, contrast, and intensity of an image. An interactive histogram lets you shift or compress brightness values to printable limits. The histogram can also be adjusted by sampling values from the image.

Original image (left); the image with Contrast Enhancement applied and expanded tonal range (right)

To adjust image tone interactively by using a histogram

1 Click Window

Dockers

Adjustments.

2 Click the Add adjustment button

, and click Contrast Enhancement.

3 Move the Input arrows, located above the histogram, to adjust shadows and highlights.

The arrow on the left lets you darken shadow areas. The new black point value is mapped to the Output value for shadows, which is 0 by default.

The arrow on the right lets you lighten highlight areas. The new white point is mapped to the Output value for highlights, which is 255 by default.

4 Move the Gamma slider to adjust the midtones.

5 Move the Output arrows, located below the histogram, to fine-tune the contrast.

To lighten dark areas, move the left arrow to the right.

To darken light areas, move the right arrow to the left.

You can also
Adjust image color	Before adjusting the tone, choose a color channel from the Channel list box.
Automatically redistribute pixels across the tonal range	Click the Auto-adjust button .
Set black point and white point by sampling pixels in the image	Click the Sample color from shadows button to sample shadow areas, or click the Sample color from highlights button to sample highlight areas.

The histogram displays adjusted values as a black outline and original values as gray shading.

Local Equalization

The Local Equalization filter lets you enhance the contrast near image edges and reveals details in both light and dark regions. The filter uses neighboring pixels to create a stylized effect.

Original image (left); the image with Local Equalization applied (right)

You can apply this adjustment non-destructively from the Effects docker and destructively from the Adjust menu.

Histogram Equalization

The Histogram Equalization filter lets you view the tonal range of an image and redistribute the balance of shadows, midtones, and highlights in the composite channel or in individual color channels according to a preset histogram model.

You can apply this adjustment non-destructively from the Effects docker and destructively from the Adjust menu.

Sample/Target Balance

The Sample/Target Balance filter lets you shift the tonal range of an image by sampling specific image areas. You can take samples from shadow, midtone, and highlight areas, and set target tonal values by choosing colors from a color model. For example, if you want to increase the tonal range, you can sample a shadow area to set the target color to black, and then sample a highlighted area to set the target color to white. You can also shift the tonal range for a specific color channel. The tonal range is displayed as a histogram.

You can apply this adjustment non-destructively from the Effects docker and destructively from the Adjust menu.

Auto Balance Tone

The Auto Balance Tone filter equalizes shadows, midtones, and highlights in an image by automatically redistributing the pixel values throughout the tonal range.

You can apply this adjustment non-destructively from the Effects docker and destructively from the Adjust menu.

Tone Curve

The Tone Curve filter lets you perform color and tonal corrections by adjusting either individual color channels or the composite channel (all channels combined). Individual pixel values are plotted along a tone curve that appears in a graph and represents the balance between shadows (bottom of graph), midtones (middle of graph), and highlights (top of graph). The x-axis of the graph represents the tonal values of the original image or the input values; the y-axis of the graph represents the adjusted tonal values or the output values.

The tone curve shows the balance between the shadows, midtones, and highlights of an image. (left) The tone curve of an image before tonal adjustments. (right) This example shows a small adjustment to the tonal range, in which pixel values of 100 are replaced with pixel values of 130 to lighten the midtone areas.

You can fix problem areas by adding nodes to the tone curve and dragging the curve. If you want to adjust specific areas in an image, you can use the Color eyedropper (Sample tone from image) tool and select the areas in the image window. You can then drag the nodes that appear on the tone curve to achieve the effect you want.

Original image (top); the image with adjusted tonal range (bottom)

The histogram lets you view the adjusted tonal range and evaluate the results. For more information about histograms, see Histograms.

To fine-tune your adjustments, you can choose a curve style from the Style list box. For example, you can redraw the curve by using freehand lines or straight line segments.

In addition, you can equalize the tonal range of an image by clicking the Auto-balance tone button. To specify the outlying pixels (clipped pixels) at each end of the tonal range, you can click the Black and White limits button and type values in the White limit and Black limit boxes.

You can apply this adjustment non-destructively from the Adjustments docker or the Effects docker, and destructively from the Adjust menu.

When accessing the Tone Curve filter from the Adjust menu or the Effects docker, you can adjust the color and tone of an image by applying a preset from the Presets area. You can also save tone settings as presets to use with other images.

Light

The Light adjustment lets you adjust the brightness and contrast across the entire image as well as brighten or darken specific areas of the images such as its highlights, shadows, and midrange tones.

To use the Light adjustment

1 Click Window

Dockers

Adjustments.

2 In the Light area of the Adjustments docker, move any of the following sliders:

• Brightness slider — brightens or darkens an entire image. This control can correct exposure problems caused by too much light (overexposure) or too little light (underexposure) at the time the photo was taken. If you want to lighten or darken specific areas of an image, you can use the Highlights, Shadows, and Midtones sliders.

• Contrast slider — increases or decreases the difference in tone between the dark and light areas of an image. Moving the slider to the right makes the light areas lighter and the dark areas darker. For example, if the image has a dull, gray tone, you can sharpen the detail by increasing the contrast.

• Intensity slider — increases or decreases the intensity of colors. Contrast and intensity usually work together because increasing the contrast can wash out detail in shadows and highlights; however, increasing the intensity can restore this detail.

Adjusting the brightness and contrast of an image can reveal more image detail.

• Highlights slider — lets you adjust brightness in the lightest areas of an image. For example, if you take a photo with a flash, and the flash washes out the foreground subjects, you can move the Highlights slider to the left to darken the washed-out areas of the image. You can use the Highlights slider in conjunction with the Shadows and Midtones sliders to balance the lighting.

• Shadows slider — lets you adjust the brightness in the darkest areas of an image. For example, a bright light behind a photo subject (backlighting) at the time a photo is taken can cause the subject to appear in shadow. You can correct the photo by moving the Shadow slider to the right to lighten the dark areas and reveal more detail. You can use the Shadows slider in conjunction with the Highlights and Midtones sliders to balance the lighting.

• Midtones slider — lets you adjust the brightness of the midrange tones in an image. After adjusting the highlights and shadows, you can use the Midtones slider to fine-tune the image.

Brightness/Contrast/Intensity

The Brightness/Contrast/Intensity filter lets you change the brightness, contrast, and intensity of an image. You can shift pixel values up or down the tonal range. Adjusting the brightness lightens or darkens all colors equally. Contrast and intensity usually work together because increasing the contrast can wash out detail in shadows and highlights; however, increasing the intensity can restore this detail.

You can apply this adjustment non-destructively from the Effects docker and destructively from the Adjust menu.

Gamma

The Gamma filter lets you reveal detail in a low-contrast image without significantly affecting the shadows or highlights. With this filter, the tonal correction of the image is based on the perception of tones relative to the surrounding area. For example, if you place a circle filled with 10 percent gray on a black background, and an identical gray circle on a white background, the circle surrounded by black appears lighter than the circle surrounded by white, even though the brightness values are identical. The Gamma filter affects all image values, but it is curve-based; consequently, changes are weighted toward the midtones.

You can apply this adjustment non-destructively from the Adjustments docker or the Effects docker, and destructively from the Adjust menu.

White Balance

The White Balance adjustment can help you achieve accurate colors in your photos by correcting color casts in your image. Color casts are typically caused by the lighting conditions when a photo is taken, and they can be influenced by the processor in your camera or scanner.

To correct a color cast

1 Click Window

Dockers

Adjustments.

2 In the White Balance area of the Adjustments docker, move any of the following sliders:

• Temperature slider — lets you correct color casts by "warming" or "cooling" the color in an image to compensate for the lighting conditions at the time the photo was taken. For example, to correct a yellow color cast caused by taking a photo indoors in dim incandescent lighting, you can move the slider toward the blue end to increase the temperature values (based on degrees Kelvin). Lower values correspond to low lighting conditions, such as candlelight or light from an incandescent light bulb; these conditions cause an orange cast. Higher values correspond to intense lighting conditions, such as sunlight; these conditions cause a blue cast.

• Tint slider — lets you correct color casts by adjusting the green or magenta in an image. You can add green by moving the slider to the right; you can add magenta by moving the slider to the left. Moving the Tint slider after using the Temperature slider lets you fine-tune an image.

• Saturation slider — lets you adjust the vividness of colors. For example, by moving the slider to the right, you can increase the vividness of a blue sky in an image. By moving the slider to the left, you can reduce the vividness of colors. You can create a black-and-white photo effect by moving the slider all the way to the left, so that all color in the image is removed.

Correcting a color cast

You can also apply this adjustment non-destructively from the Effects docker and destructively from the Adjust menu.

Desaturate

The Desaturate filter creates a grayscale image without changing the color mode. For example, you can apply the Desaturate filter to a color photo to create a black-and-white photo effect. It automatically reduces the saturation of each color to zero, removes the hue component, and converts each color to its grayscale equivalent.

You can apply this adjustment non-destructively from the Effects docker and destructively from the Adjust menu.

Grayscale

The Grayscale filter lets you produce a black and white image without changing the color mode. It also allows you to adjust individual colors for conversion, which modifies the intensity of the gray tones in the image when it’s converted. In addition, you can tint the image by modifying the hue and saturation. For example, you can add a tint to an image to produce a Sepia effect.

A photo before (left) and after (right) applying the Grayscale filter.

You can apply this adjustment non-destructively from the Effects docker and destructively from the Adjust menu.

Hue/Saturation/Lightness

The Hue/Saturation/Lightness filter lets you change the hue, saturation, and lightness values of an image or channel. Hue represents color; saturation represents color depth or richness; and lightness represents the overall percentage of white in an image.

You can apply this adjustment non-destructively from the Adjustments docker or the Effects docker, and destructively from the Adjust menu.

Vibrance

The Vibrance filter allows you to increase the saturation in an RGB image without causing clipping or "blowing out" the image. Clipping occurs when an area of an image is too bright and the color details in the area are lost, which can occur when you increase the saturation in an image indiscriminately. The Vibrance filter adjusts saturation proportionally by increasing the saturation of the less-saturated colors more than that of the saturated colors. This filter is useful for adjusting the saturation of images that include a person in front of a detailed background. For example, it allows you to boost the saturation of the background details without adversely affecting the skin tone of the person in the image.

A photo before (left) and after (right) applying the Vibrance filter.

You can apply this adjustment non-destructively from the Adjustments docker or the Effects docker, and destructively from the Adjust menu.

Selective Color

The Selective Color filter lets you change a color by changing the percentage of the component process colors (CMYK values) in a color spectrum (reds, yellows, greens, cyans, blues, and magentas). This filter also lets you add process color to the grayscale tonal component of an image. Selective color modifications increase and decrease the percentage of cyan, magenta, yellow, and black pixels that make up each primary color in the color spectrum. For example, decreasing the percentage of magenta in the reds spectrum results in a color shift toward yellow. Conversely, increasing the percentage of magenta in the reds spectrum causes a color shift toward magenta and an overall increase in red. The extent of color modification depends on the adjustment percentage method you choose.

You can apply this adjustment non-destructively from the Adjustments docker or the Effects docker, and destructively from the Adjust menu.

Channel Mixer

You can mix color channels to balance the colors of an image. For example, if an image has too much red, you can adjust the red channel in an RGB image to improve image quality. For more information about mixing channels, see Color channels.

Replace Colors

The Replace Colors filter lets you replace colors in an image, editable area, or object. When you select the color you want to replace, the application also automatically selects a range of similar colors to be replaced. You can select the original and replacement colors from the image or from a color picker.

The Replace Colors adjustment has been applied to replace all reds with purple.

To add or remove colors from the selection, you can adjust the hue and saturation range. You can also select and replace a single color in the image. To prevent abrupt color changes, you can smooth the transition between selected and unselected pixels. You can also set the hue, saturation, and lightness for the new color.

An orange color was selected from the image.

The orange in the shirt is replaced with blue, but some orange and red colors still remain (top). The saturation range is adjusted to select and replace those colors (bottom).

To replace colors

1 Click Window

Dockers

Adjustments.

2 Click the Add adjustment button, and click Replace Colors.

3 In the Original area, click the eyedropper tool

and sample a seed color from the image, or choose a color from the color picker.

The Range control show the range of selected colors.

4 In the New area, click the eyedropper tool and sample a color from the screen, or choose a color from the color picker.

5 To smooth the transition between selected and unselected pixels, move the Smooth slider.

You can also
Adjust the selected hue range	Point to one of the edges of the color band on the Hue range ring, and when the hand cursor appears, drag up and down. To shift the entire hue range of selected colors, click the handle of the color band on the Hue range ring, and drag around the ring. Note: When the color band is small, only pixels that are very similar to the color you selected are selected and replaced; when the color band is bigger, more pixels are selected and replaced. Adjusting the selected hue range
Adjust the saturation range of a hue’s shades to be included in the selection	Point to the inner or outer edge of the color band on the Saturation range circle, and drag when the pointer changes to a hand.
Replace a single color	Enable the Single color check box.
Set the hue, saturation, and lightness of the output color	Move the Hue, Saturation, and Lightness sliders, respectively.

Some versions of Corel PHOTO-PAINT let you use only an earlier version of this adjustment, which is known as Replace Colors (Legacy).

The Replace Colors (Legacy) adjustment also lets you edit Replace Colors adjustments applied non-destructively to images that are saved to the previous version of Corel PHOTO-PAINT.

You can also replace colors non-destructively from the Effects docker and destructively from the Adjust menu.

Color Balance

The Color Balance filter lets you adjust the color balance of an image by shifting the colors between complementary pairs of the primary RGB color values and secondary CMY color values. This method is useful for correcting color casts. For example, if you want to tone down the red in a photo, you can shift the color values from red to cyan. You can also change the hue values to change the colors used in an image.

You can apply this adjustment non-destructively from the Effects docker and destructively from the Adjust menu.

Color Hue

The Color Hue filter lets you change the hue of an image by clicking sample thumbnails. For example, you can remove a yellow cast from an image by clicking a thumbnail that adds blue. The intensity of the effect increases by a specified amount each time you click the thumbnail. The thumbnails also let you preview the color hue adjustment.

You can apply this adjustment non-destructively from the Effects docker and destructively from the Adjust menu.

Color Tone

The Color Tone filter lets you change the brightness, saturation, and contrast of colors by clicking sample thumbnails. The intensity of the effect increases by a specified amount each time you click the thumbnail. The thumbnails also let you preview the color tone adjustment.

You can apply this adjustment non-destructively from the Effects docker and destructively from the Adjust menu.