Relationship Between the Tone Curve Image Brightness | Canon 4.1

S T E P 3

The Relationship Between the Tone Curve

and Image Brightness

The Gamma values fall with a range of 0.01 to 10.00. A value of 1 appears as a straight line in the graph, and if the value is any value other than one, the line on the graph will appear curved. The relationship between the shape of the curve and image brightness is explained below.

Gamma Value = 1

Input and output and are equal and the curve appears as a straight line, and the input image is displayed on the screen without adjustment.

Gamma Value > 1

The data bends upward over the range of input values from shadows to highlights, making the adjusted image brighter in the display.

Gamma Value < 1

The data bends downward over the range of input values from shadows to highlights, making the adjusted image darker in the display.

OutputOutputOutput

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Input

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Input

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Input

CAUTION

•The tone curve cannot be adjusted manually in one of the color scan modes when ColorSync is selected because the color balance is adjusted automatically.

•The tone curve cannot be adjusted for a black and white image because mid-tones are shown as either black or white. To adjust the brightness of a black and white image, use the threshold setting (p. 48).

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Image 46

Canon 4.1 manual Relationship Between the Tone Curve Image Brightness, Gamma Value =

Contents

Users Guide How to Make Best Use of the Manuals When you open the box Where to Look How to Use this GuideAbout the Conventions Used in this Guide Table of Contents Adjusting Scanned Images Installing Plug-in Module CS-U Operating Environment Control Panel Features Pp -20Image Size Scanning Procedures E P Plug-in Module CS-U Special Features Start Plug-in Module CS-U p Install Plug-in Module CS-UQuick Start Instructions Position materials for scanning and preview them. p Select the area to be scanned by clicking and dragging Verify Image Quality with the Browser Function beforeSpecify the Area of the Image to be Scanned Mouse pointer over the image Click on the Scan button Scan the ImageSave the Scanned Image Save the image with Adobe Photoshop LE or other plug-in E P Displaying the Plug-in Module CS-U Control Panel RGB Values Operating Procedures Positioning Originals ProceduresPlace the original on the scanners document glass Previewing Click on the Preview button Selecting the Output Device Setting the Resolution and Magnification Output Device Resolution= 720 dpi, Magnification= 100% To Set the Magnification Factor Set the desired magnification factor on the control panel Setting the Scan Mode Click the arrow beside Scan Mode Select a scan mode from the pop-up menu Verifying the Image before Scanning To Verify the Image Rotating the Image Use these buttons to rotate the image Output Device Setting PreferencesAspect Ratio Unit Preview Window Close Plug-in After Scan Reset Default SettingsShut off lamp time Platen/Film Operating Procedures Scanning Setting the Scan Area Position the pointer in the preview window Zooming Procedures to ZoomSelect the area you want to enlarge with the zoom function Click on the Zoom In button Specify the Scan Area ScanningTo Initiate the Scan Click close box to guit the Plug-in Module CS-U Saving Scanned Images Enter a name for the file and click the Save button Scanning Film Auto Exposure Save Exposure Data Click on the Scan button Remove Dust and Scratches CanoScan D2400U only Black & White Bit/14/16bit Grayscale and 24-bit/42/48bit ColorBit Color Tone Adjustment Tone Adjustment Dialog Histogram Settings How to Interpret Histograms To Adjust a Histogram How to Adjust Histograms Click on the OK button Shadow Mark Tone Curve Settings Manipulating the Graph To Edit the Tone Curve Click the OK button Relationship Between the Tone Curve Image Brightness Gamma Value = Contrast Brightness and Contrast SettingsBrightness To Adjust the Brightness and Contrast Adjusting the Color Balance Operating Procedure Matching the Gamma Value to the Display Characteristics Gamma Value SettingsGamma value To Change the Gamma Value Settings Adjusting the Threshold Value To Set the Threshold Value Recommended Auto Tone CorrectionTo Set the Auto Tone Correction ColorSync Unsharp Mask Open the Image menu and select Unsharp Mask Descreen Open the Image menu and select Descreen High-speed Scan Mode Select High-speed Scan Mode from the Image menu To Save Settings in a Settings File Saving/Recalling SettingsClick the Save button To Recall a Settings File Matching Scan Resolution to Purpose Scanning Techniques Appendices Troubleshooting Problem Scan button cannot be selected Problem Scanning is taking a long time Problem Scanning quality is poor Error Message Cause Error MessagesResponse Glossary Color Dot Histogram Optical ResolutionGrayscale Image File Plug-in Software ResolutionPixel Preview Area Threshold Value Scan ModeShadows Tone Curve Index Output device 7, 11, 18, 25 Scan 12, 33 Scan area 11 Canon Customer Support Help Desk Canon U.S.A., INC