Adjusting color and tone

You can improve the quality of images by adjusting the color and tone to correct color casts and exposure problems or to alter specific colors.

In this section, you’ll learn about

•adjusting image color and tone

•working with color channels

Adjusting image color and tone

Corel PHOTO-PAINT provides you with filters and tools to make adjustments to the color and tone of images. When you adjust the color and tone, you adjust elements such as hue, saturation, brightness, contrast, or intensity. If you want to adjust the color and tone of the entire image, you can apply an adjustment filter directly to the image or apply a lens which exists on a separate object layer and can be edited without changing the original image. For information about lenses, see “Working with lenses” on

page 409.

You can adjust part of an image by editing the size and shape of a lens or by creating an editable area before applying an adjustment filter. For information about editable areas, see “Masking” on page 413.

Choosing color and tone filters

Some filters adjust the image automatically, while others give you varying degrees of control. For example, the Auto equalize filter adjusts the tonal range automatically, while the Tone curve filter lets you pinpoint and adjust tone, or color, using separate color channels. More advanced filters, such as the Tone curve filter and the Contrast enhancement filter, are precise and can correct a variety of problems, but require practice. If you are new to color and tone correction, consider the following options:

•Automatic adjustments: apply the Auto equalize filter. This filter improves the tone of most images instantly. If the filter doesn’t correct the problem, you can undo the change and try another filter.

•Quick tone adjustments: apply the Color tone filter to brighten or darken an image, or improve contrast using thumbnail buttons. You can also try the Brightness/Contrast/Intensity filter. After you adjust the brightness, you must adjust the contrast and intensity to retain image detail.

•Quick color adjustments: apply the Color hue filter to adjust the color using thumbnail buttons, or apply the Color balance filter which lets you increase or decrease specific color values. For example, if an image has a green cast, you can remove some green or add a contrasting color (magenta) to neutralize the green cast.

Adjusting tone interactively

You can view the tonal range of an image using a histogram to evaluate and adjust the color and tone of an image. For example, a histogram can help you determine if there is hidden detail in an underexposed photo. A histogram has a horizontal bar chart that plots the brightness values of the pixels in your image on a scale from 0 (dark) to 255 (light). The left part of the histogram represents the shadows of an image, the middle part represents the midtones, and the right part represents the highlights. The height of the spikes indicates how many pixels are at each brightness level. For example, a large number of pixels in the shadows (the left side of the histogram) indicates the presence of image detail in the dark areas of the image.

A histogram is available with the following filters:

•Contrast enhancement

•Histogram equalization

•Sample/Target balance

Adjusting the color and tone using brush strokes

You can adjust the brightness, contrast, hue or saturation in part of an image by applying brush strokes. You can use preset brushes or create a custom brush. For more information, see “Creating custom brushes” in the Help.

To adjust image color and tone

1Click Image ` Adjust, and click an adjustment filter.

2In the filter’s dialog box, specify the settings you want.

To adjust image tone interactively

1 Click Image ` Adjust ` Contrast enhancement.

2Move the Input value clipping arrows to adjust shadows and highlights.

The arrow on the left lets you darken shadow areas. Drag the arrow until it points to the area where the histogram starts to spike.

The arrow on the right lets you lighten highlight areas. Drag the arrow until it points to the area where the histogram stops spiking.

3Move the Gamma slider to adjust the midtones.

4Move the Output range compression arrows to fine-tune the contrast: The arrow on the left lets you lighten darker areas as you drag the arrow to the right.

The arrow on the right lets you darken light areas as you drag the arrow to the left.

You can also

To adjust image color and tone using brush strokes

1Select an object or the background image.

2Open the Brush flyout , and click the Effect tool .

3On the property bar, open the Effect tool picker, and click one of the following:

•Brightness tool — brightens or darkens the image

•Contrast tool — increases or decreases the contrast

•Hue tool — shifts all hues along the color wheel by the number of degrees that you specify in the Amount box

•Hue replacer tool — retains the brightness and saturation of the original colors, but replaces all hues with the current paint color

•Sponge tool — saturates or desaturates the colors

•Dodge/Burn tool — brightens (overexposes) or darkens (underexposes) the image

•Tint tool — tints the image using the current paint color