Xerox 7600i User's Guide download pdf (Page 149)

Xerox 7600i

User’s Guide

149

Choosing contrast values

While Brightness adds the same amount of gray or white to all pixels in the image, Contrast adjusts the pixels

based on the pixel color level. For instance, increasing the contrast level will add white to light colored pixels and gray

to dark pixels to make the difference between color levels in the image crisper. Decreasing the contrast level will

have the opposite affect, where light colored pixels are modified with gray and dark pixels are modified with white

to make the transition of colors in the image appear smoother.

Adjusting the contrast level is based on how you want the image to appear and there is no standard to adhere to.

Contrast works in conjunction with brightness for image enhancement, when decreasing the brightness level, the

overall image becomes darker, in which case you may want to increase the contrast level so that the differences

between the lighter and darker portions of the image are clearer.

Below are some recommended options for contrast image correction based on the original document quality.

•Original documents of good quality - 50%

• Pencil written letters, forms, or drawings - 55% to 65%

• Faded pictures or old documents with faded text - 60% to 70%

• Light colored carbon copy paper, such as yellow or pale pink or pale green, with light text - 45% to 55%

•Newspaper or magazine pages - 55% to 70%

• Book pages - 60% to 75%

• Pictures taken inside or in the shade - 40% to 60%

Color image contrast examples

The examples below show the original image at the default setting of 50% contrast level, 25% contrast and 75%

contrast.

Technical note:

Most monitors have a contrast setting that is user adjustable. When viewing scanned images on-screen, versus

printing the image, the contrast setting of the monitor may affect how clear a scanned image looks when compared

to the original. If the scanned image is too different from the original image, or if adjusting the scanned contrast

level does not modify the image how you want, try adjusting the monitor's contrast level. Refer to the monitor's user

guide for adjusting the contrast level and see if the manufacturer has any recommended settings.

Black background scanners:

Some scanners have a black background plate. A black background results in more precise cropping results and skew

detection. However, when scanning thin paper, such as carbon copy paper or ruled writing paper, which are less than

18lb paper weight, the background may “bleed” through into the final image and make the image darker than it

should be. In that case, try adjusting the brightness level between 40% and 60%, then adjust the contrast level

between 60% and 80%.

Contrast: 25% Contrast: 50% Contrast: 75%

1 2 ... 144 145 146 147 148 149 150 151 152 153 154 ... 181 182

No comments

Xerox 7600i User's Guide Page 149