Canon 4.1 manual Gamma Value Settings, Matching the Gamma Value to the Display Characteristics

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Gamma Value Settings

By adjusting the gamma value, you can more closely match brightness of the displayed image to the printed image. Adjust this value if what you see on the screen is very different from your printout.

Hint

•You cannot use this feature with the black and white scan mode, or with the color scan modes when ColorSync is selected.

Matching the Gamma Value to the Display Characteristics

Not all screen displays reproduce color tones in exactly the same way, and this reproduction method is expressed as a gamma value from 1.4 to 2.2 and normally reproduces a slightly dark image.

In order to avoid this and reproduce an image that is faithful to the original, the gamma value must be adjusted in Plug-in Module CS-U. Plug-in Module CS-U can adjust the pre-set screen gamma value of 1.8, but if the screen has a gamma value other than 1.8 then the gamma value for that screen must be set.

Gamma value

Plug-in Module CS-U and the screen display have different gamma values. During a scanning job Plug-in Module CS-U receives the image read from the scanner as input and sends it to the parent application as output. The gamma value in this interval where Plug-in Module CS-U converts input to output is the Plug-in Module CS-U gamma value.

On the other hand, the data received from Plug-in Module CS-U as input is sent to the screen display as output. The gamma value in this interval where the image input from Plug-in Module CS-U is converted to output for the screen display is the screen display gamma value.

Setting the screen display gamma value causes the scanner gamma value to be calibrated automatically as the inverse value. For example, if the screen display gamma value is set for 1.8, then the scanner gamma value is calibrated for 0.56 (the inverse of 1.8).

Hint

•Please read the documents shipped with your display or contact the manufacturer’s customer service department to obtain the correct gamma value for your particular display model.

•If you intend to adjust the color tone with ColorSync™, change the settings in the ColorSync™ control panel (found within the Control Panels folder) and do not manually change the gamma value settings as described in the following pages.

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Contents Users Guide How to Make Best Use of the Manuals When you open the boxAbout the Conventions Used in this Guide How to Use this GuideWhere to Look Table of Contents Adjusting Scanned Images Installing Plug-in Module CS-U Operating EnvironmentControl Panel Features Pp -20Image SizeScanning Procedures E PPlug-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. pSelect 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 imageClick on the Scan button Scan the ImageSave the Scanned Image Save the image with Adobe Photoshop LE or other plug-inE P Displaying the Plug-in Module CS-U Control Panel RGB ValuesOperating Procedures Place the original on the scanners document glass ProceduresPositioning Originals Previewing Click on the Preview buttonSelecting 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 panelSetting the Scan Mode Click the arrow beside Scan Mode Select a scan mode from the pop-up menuVerifying the Image before Scanning To Verify the ImageRotating the Image Use these buttons to rotate the imageAspect Ratio Setting PreferencesOutput Device Unit Preview WindowClose Plug-in After Scan Reset Default SettingsShut off lamp time Platen/FilmOperating Procedures Scanning Setting the Scan Area Position the pointer in the preview windowSelect the area you want to enlarge with the zoom function Procedures to ZoomZooming Click on the Zoom In button Specify the Scan Area ScanningTo Initiate the Scan Click close box to guit the Plug-in Module CS-USaving Scanned Images Enter a name for the file and click the Save buttonScanning Film Auto Exposure Save Exposure DataClick on the Scan button Remove Dust and Scratches CanoScan D2400U only Bit Color Bit/14/16bit Grayscale and 24-bit/42/48bit ColorBlack & White Tone Adjustment Tone Adjustment DialogHistogram Settings How to Interpret HistogramsTo Adjust a Histogram How to Adjust HistogramsClick on the OK button Shadow MarkTone Curve Settings Manipulating the GraphTo Edit the Tone Curve Click the OK buttonRelationship Between the Tone Curve Image Brightness Gamma Value =Brightness Brightness and Contrast SettingsContrast To Adjust the Brightness and Contrast Adjusting the Color Balance Operating ProcedureGamma value Gamma Value SettingsMatching the Gamma Value to the Display Characteristics To Change the Gamma Value Settings Adjusting the Threshold Value To Set the Threshold ValueRecommended Auto Tone CorrectionTo Set the Auto Tone Correction ColorSyncUnsharp Mask Open the Image menu and select Unsharp MaskDescreen Open the Image menu and select DescreenHigh-speed Scan Mode Select High-speed Scan Mode from the Image menuClick the Save button Saving/Recalling SettingsTo Save Settings in a Settings File To Recall a Settings File Matching Scan Resolution to Purpose Scanning TechniquesAppendices Troubleshooting Problem Scan button cannot be selected Problem Scanning is taking a long time Problem Scanning quality is poor Response Error MessagesError Message Cause Glossary Color DotHistogram Optical ResolutionGrayscale Image FilePlug-in Software ResolutionPixel Preview AreaThreshold Value Scan ModeShadows Tone CurveIndex Output device 7, 11, 18, 25Scan 12, 33 Scan area 11 Canon Customer Support Help Desk Canon U.S.A., INC