| # Adjust Image Colors
Table of Contents How To... | To adjust image colors, in the Options Panel, click Adjustment bar. The Adjustment tab will appear. From the Adjustment tab, you can adjust the tonal range of an image:
Brightness — you can make simple adjustments to the tonal range of an image. Brightness setting determines the level of light and dark shades in an image. A pure white image has maximum brightness, whereas a pure black image has minimum brightness. Brightness is distinct from contrast, which measures the range between the darkest and lightest shades in an image. Contrast — you can make overall adjustment to the image. Contrast setting determines the relationship between the light and dark areas of an image. A high contrast image is a black and white image with no gray shades. A low contrast image shows many midrange gray shades. An image with low contrast tends to look dull and flat. Highlight — you can set highlight level for the whole image. Increasing the highlight level value lightens the light areas of your image, and decreasing the highlight value darkens them. Shadow — you can set shadow level for the whole image. Increasing the shadow level value darkens the dark areas of your image, and decreasing the shadow level lightens the dark areas of your image. Gamma — you can set the contrast affecting the mid-level grays or midtones of an image. Adjusting the image gamma allows you to change brightness values of the middle range of gray tones without altering the shadows and highlights.
The adjustments of Brightness/Contrast, Highlight/Shadow and Gamma levels are made separately to every available color channel:
For color images scanned in 256 Colors or True Color, RGB mode, you can adjust Brightness/Contrast and Gamma levels for the Red, Green, Blue and RGB channels; the adjustments to RGB channel affect each of the Red, Green and Blue channels. You can adjust Highlight/Shadow levels for the RGB channel only. For the images scanned in Gray 256 Scales mode, you can adjust Brightness/Contrast, Highlight/Shadow and Gamma levels for the Gray channel only. For the images scanned in Lineart B/W or Halftone B/W mode, you cannot adjust any of the Brightness/Contrast, Highlight/Shadow and Gamma settings.
To make adjustments for a color channel, select the channel in the Channel list:
| ###### To do the following… | ###### In the Channel list, click the following item:
| Adjust Brightness/Contrast and Gamma levels for the Red color channel | Red
| Adjust Brightness/Contrast and Gamma levels for the Green color channel | Green
| Adjust Brightness/Contrast and Gamma levels for the Blue color channel | Blue
| Adjust Brightness/Contrast, Highlight/Shadow and Gamma levels for the RGB color channel | RGB
| Adjust Brightness/Contrast, Highlight/Shadow and Gamma levels for the Gray color channel | Gray
You can use automatic color adjustment. When automatic adjustment is applied, ScanThru automatically sets the Brightness/Contrast, Highlight/Shadow and Gamma levels for all color channels. To adjust the Brightness/Contrast, Highlight/Shadow and Gamma levels for all color channels automatically, click Auto.
You can also apply color inversion to the image. To invert the image colors, select the Invert check box. When you invert image colors, all image color values are changed to the opposite ones (for example, black color is changed to white).
The color inversion that is applied to the image uses the current Brightness/Contrast, Highlight/Shadow and Gamma level settings.
##### Related Topics:
Working With ScanThru Options Panel Image Type Color Channels