Colour Adjustment: The Colour Adjustment dialog box is effective for removing colour casts from photos. Adjustments are made by moving sliders for the Red/Cyan, Green/Magenta and Blue/Yellow colour properties, with changes applied to highlights, midtones and shadow areas as required.
The general rule for removing a colour cast is to add more of the opposite colour. In the dialog box shown left, the original thumbnail has a red colour cast. This has been removed by adding more cyan, and a small amount of magenta to remove a slight green cast. In both cases, changes were made to midtone areas only.
The effects from moving the sliders are previewed in the righthand thumbnail.

Hue and Saturation: Controls in the Hue and Saturation dialog box (shown left) can be used as follows :

Hue: shifts the hue (colour) value of each pixel in an image by the amount specified. For example, a yellow pixel will become blue if you set the hue value to 180.

Saturation: increases or decreases the strength of colour in an image. Fully reducing saturation results in a grayscale image, while fully increasing makes colours very rich.

Lightness: adds levels of white or black over the image depending on the value selected. Fully reducing lightness makes an image completely black, while fully increasing lightness makes it completely white.

Method: These options determine how colours in an image are manipulated.

Master: The upper coloured bar represents the original hues of an image, while the bottom bar indicates hues that will replace them. For example, if the red colour in the upper bar is in line with blue in the bottom bar, red colour in an image will be replaced with the indicated blue color.

Range: This uses 4 slider controls between the 2 coloured bars to limit any adjustments to specific colour ranges within an image. The central dark gray segment is the area that adjustments will mainly effect, while the 2 light gray outer segments indicate colour tones that will be lesser effected. You can move the 4 slider controls as a group into the required color range by moving the dark gray area, then seperating the sliders accordingly (see Dialog box above). Restricting colour adjustments to a limited range is useful for landscape photos when you wish to increase, for example, the lightness/darkness and colour saturation of skies. In the example above left, the range method has been used to restrict colour adjustments to blue tones on the image, leaving other colours unaffected.

Colorize: This method is useful for adding tones of a specific colour to an image. In the dialog box shown above, the Colorize method has been used to change the original colours into a sepia toned image. The bottom coloured bar changes as the hue slider is moved, showing the colour represented by the number next to the hue slider control. Once the hue has been selected, further adjustments can be made using the Saturation and Lightness sliders where required.

If the Preview box is checked, any adjustments will be shown in the right hand thumbnail image.

Colour Replacement: The Colour Replacement option is similar to the Range method available in Hue and Saturation, but gives more precise control over colour selection and adjustment. The eyedropper is used to select a colour in the left hand thumbnail, then the Similarity slider adjusted to select the range of colours (related to the eyedropper selection) to be effected.

In the example shown left, a point on the grey cloud was selected with the eyedropper, then Saturation increased and Lightness decreased to make the clouds more prominent. The eyedroppers with plus and minus signs can be used to add or subtract a colour from a selection.

Mask View can be used in conjunction with the Similarity slider to give a visual indication of how changes to hue and saturation will effect the image. Black areas in Mask view will not be effected by adjustments, while white areas will be fully effected. Midtone areas will be partially effected by selected hue and saturation settings.

Colour Balance - Setting a Black Point
Some photographs often look a little muddy and flat because parts of the image that should be black appear as dark brown. Setting the black point on an image can be done easily and quickly with Colour Balance.

When the dialog box is opened, click on the Smart tab then use the zoom and pan tools to move to an area of the image that should be black, such as shadow areas. Use the eyedropper tool and select the colour you wish to replace. The selected colour then shows in the Current colour box. In the example shown left, the shadow from the Millenium Eye on the building roof was selected as the colour to adjust.

To replace the selected colour, click on the Desired colour box, and the Ulead Colour Picker appears (see right). Select the desired colour from the options available, click ok, then check the effect in the Preview window. If the result is too dark or light, repeat the process using a different black point until the desired effect is obtained.





















Colour Balance - Overall Adjustment
In addition to setting black (or white) points on an image, Colour Balance can also be used for adjustments across the whole range of image colours using Preset options in the dialog box. The current image colours are displayed in the centre cell, with variations shown around it, for example, warmer or cooler toned versions of the original. Clicking on one or more of the thumbnails will apply the selected colours to the image.

Tone Balance specifies the type of color adjustment applied to an image. Highlight adjusts light areas, Shadow modifies dark areas, while Midtone adjusts intermediate tones. When the Auto option is selected, adjustments are applied to all tones on the image.

When Show clipping is checked, the thumbnails show image parts that are converted to pure black or pure white due to adjustments in brightness and contrast.