Canon CS-S 4.3 manual Gamma Adjustments, Histogram Techniques

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CONTENTS

 

 

Chapter 5

59

 

 

 

Scanning Techniques

 

GLOSSARY

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

INDEX

 

 

 

 

 

 

 

 

 

If you have a high-contrast image, or a black and white continuous tone

 

 

 

photograph that needs minor adjustment, the brightness and contrast

 

 

 

settings can improve the image.

 

 

 

 

If you have an image with multiple tones, such as most color images, the

 

 

 

brightness and contrast settings may not provide the desired results. The

 

 

 

Gamma, Histogram, and Special Tone Curves, which let you adjust the

 

 

 

midtone range and contrast as well as individual color ranges, may give you

 

 

 

more satisfying results.

 

 

 

 

Gamma Adjustments

 

 

 

 

The Gamma curve tool adjusts the midtones in an image in relation to

 

 

 

themselves. Adjusting the gamma setting can improve the visibility of color

 

 

 

and grayscale images, particularly ones with many midtones. Gamma values

 

 

 

above 1.00 lighten the midtones of an image, and values below 1.00 darken

 

 

 

the midtones. The gamma settings can range from

0.10 and 10.00, but for

 

most color photographs, the range is between 1.00 and 2.00. The photographs scanned for the illustrations in this manual had many dark midtones in the background, so a lower setting was used to enhance the background.

Histogram Techniques

The histogram displays a graph of all the pixels in the image, sorted by tone. The darkest pixels are grouped to the left, the midtone pixels in the middle, and lightest tone pixels to the right. The triangular sliders at the bottom of the histogram reflect the default settings of Black-Point 0, Mid-point 128, and White-point 255.

The histogram tools let you change the distribution of dark-tone, midtone, and white-tone pixels in your image, to correct the image. Any changes you make are immediately displayed in the preview image.

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Contents UsersGuide Quick Start Guide How to Make Best Use of the ManualsCopyright Notice Contents Scanning Devices Glossary Index Setting Up ScanGear Toolbox CSHardware Introduction to ScanGear CS-SWelcome to ScanGear CS-S System RequirementsSoftware Feature ListAbout ScanGear CS-S Windowless Mode About ScanGear CS-SAssumptions About this User’s GuideCanon Technical Support Installing ScanGear CS-S Installing ScanGear CS-SNext Steps Where to Go From HereSelecting ScanGear CS-S Removing ScanGear CS-SGetting Help in ScanGear CS-S Twain Interface Using ScanGear CS-S with an ApplicationScanning About ScanningPreview Area Features of the ScanGear CS-S WindowAcquiring an Image Status and Message Areas Settings TabsClear, Preview and Scan Buttons ToolbarPreviewing an Image Quick Start to ScanningPreparing the Scanner Contents Contents Glossary Index Now you are ready to scan Where is the Scanned Image? Scanning in Windowless UI-less ModeChanging the Preview Image Shape and Size Using the ToolbarWorking with Preview Images Creating a Negative Image Cropping Part of an ImageMoving an Image Zooming In and OutSelecting Automatic Tone Correction Reversing an ImageRotating an Image Left or Right Displaying or Hiding the RulersSpecifying How the Image is Previewed Setting Scanning Mode Setting Scan Mode, Resolution, and DimensionsTo set scanning mode Selecting a Preset Resolution Selecting Scan ResolutionDeleting a Custom Resolution Selecting a Custom ResolutionChanging a Custom Resolution Selecting Output DimensionsMaintaining Image Proportion Setting Units of MeasurementSetting Image Width and Height Setting Scale About the Tone Tab Settings Setting Image TonesSelecting a Color Channel About the Tone Curve WindowUsing the Auto Tone Setting Adjusting Contrast and Brightness Changing Gamma Curve Values Glossary Index Change Tone Using the Histogram ToolDo one of the following to change the black point Do one of the following Using Preset or Custom CurvesAbout the Curve Box Using Predefined Tone CurvesUsing Custom Tone Curves Select Special Curve list, select Edit custom curve Curve is saved in the location you specify Hints for Editing Custom Tone Curves Opening a Saved Custom Tone CurveSelecting Text Enhanced Setting General PreferencesUsing Text Enhanced for Scans About Canon ColorGear Color Matching Using Canon ColorGearTM Color MatchingSelecting a Monitor Profile Setting Up the Preview Options Image Source Configuring Scanning DevicesConfiguring a Device with ScanGear CS-S Scanning DevicesDescreen Threshold SettingTest Scanner Shut Off Lamp Time Chapter Scanning DevicesScanning Multi-Page Documents Using the Automatic Document Feeder ADFPreparing the Material to Scan Scanning TechniquesAbout Scanning Techniques Planning for the End ResultMatching Scan Resolution to Purpose Estimating Image Sizes Optical and Enhanced ResolutionsResolution and Color File Size Estimates Cropping the Image Shape What Do Those Curves Mean? Custom Tone AdjustmentsContrast and Brightness Adjustments Histogram Techniques Gamma AdjustmentsContents Contents Sampling a Tone for the Histogram About Image Color and Color Channels Enhancing Color ImagesContents Glossary Index About ScanGear Toolbox CS Using ScanGear Toolbox CSInstalling and Uninstalling ScanGear Toolbox CS About the ScanGear Toolbox CS Bar Starting ScanGear Toolbox CSRemoving a Button from the ScanGear Toolbox CS Bar Setting Up ScanGear Toolbox CSAdding a Button to the ScanGear Toolbox CS Bar Enabling or Disabling Easy Acquire Configuring Copy Settings Showing the Copy Button on the ScanGear Toolbox CS Bar Copying Acquired ImagesWith the ScanGear CS-S window open, do the following Configuring Mail Settings Showing the Mail Button on the ScanGear Toolbox CS Bar Linking a Mail ApplicationMailing Acquired Images Linking a Fax Application Configuring Fax SettingsShowing the Fax Button on the ScanGear Toolbox CS Bar Faxing Acquired ImagesConfiguring Edit or Custom Settings Linking an Edit or Custom Application Contents Selecting a ScanGear Toolbox CS Source Changing ScanGear Toolbox CS PreferencesSpecifying ScanGear Toolbox CS Appearance Cleaning Up Temporary FilesUsing ScanGear Toolbox CS Shortcut Menus Right-Clicking the Canon Scanner Monitor Icon Canon Scanner MonitorCanon Monitor Utility Display Mail Image ScanGear Toolbox CS Settings SummaryCopy Image Edit or Custom Image Fax ImagePre-Scan Checklist Frequently Asked QuestionsTop Ten List Scanner diagnostics test displays a test failed message Troubleshooting Q & aScanGear CS-S does not launch Your graphics application cannot find the scannerSome functions are grayed-out Parts of images are missing or misaligned Printing or scanning is too slowPreview image is too small on my monitor Automatic document feeder is jammedBits and Bit Depth Automatic Tone AdjustmentGlossary Acquired ImagesContents Index Color Wheel Curve ChartCustom Resolutions DefaultEasy Acquire DigitizingDpi DriverHistogram Tool Gamma CorrectionGrainy HeightMid-Tone Optical ResolutionLow Contrast Mid-Point EyedropperOutput Size Output DimensionsPreset Curves Output File FormatsRotate Left/Right ResolutionScan Mode Scan ResolutionSliders System DefaultSelection Tool Shortcut MenusTone Curve Text EnhancedThreshold ToneWidth-Height Ratio Units of MeasurementWhite-Point Eyedropper WidthIndex 104 105 106 107 108 OE-022AA 0399 CDS Canon Inc