Canon printer PIXMA MG7720 User Manual

Below is an example of correcting a bluish image.
Since  Blue and  Green  are too strong, click the  Yellow and Magenta  arrows to correct.
BeforeAfter
Note

Adjusting Saturation and Color BalanceYou can brighten colors that have faded with time or due to colorcast by using 
 (Saturation/Color
Balance) in ScanGear (scanner driver)'s  Advanced Mode tab.
Note

Move  (Slider) under Color Balance  to the left or right to emphasize the corresponding color.
Cyan & Red
Magenta & Green
Yellow & Blue
These are complementary color pairs (each pair produces a shade of gray when mixed). You can reproduce the natural colors of the scene by reducing the cast color and increasing the complementary color.
It is usually difficult to correct the image completely by adjusting only one color pair. It is recommended
that you find a portion in the image where it should be white,...

Adjusting Brightness and ContrastYou can adjust images that are too dark or bright, or too flat due to lack of contrast by using 
(Brightness/Contrast) in ScanGear (scanner driver)'s  Advanced Mode tab.
Note

Brightness
Adjust the image brightness.
Move 
 (Slider) under  Brightness to the left to darken and right to brighten the image. You can also
enter a value (-127 to 127).
DarkenedOriginal imageBrightened
Note

Adjusting HistogramYou can adjust the image color tone by using a graph (histogram) showing brightness distribution, via 
(Histogram) in ScanGear (scanner driver)'s  Advanced Mode tab.
Note

(1) Bright area(2) Dark area(3) Whole imageMore data is distributed to thehighlight side.More data is distributed to the shadow side.Data is widely distributed between thehighlight and shadow.
Adjusting Histograms (Using the Slider)
Select a  Channel , then move 
 (Black-point Slider) or  (White-point Slider) to specify the level to be
set as the shadow or highlight.

Moving the Mid-point SliderMove the Mid-point Slider to specify the level to be set as the middle of the tonal range.
Images with more data distributed to the highlight side
Move the Mid-point Slider toward the highlight side.
Images with more data distributed to the shadow side
Move the Mid-point Slider toward the shadow side.
Adjusting Histograms (Using the Droppers)
When you select a  Channel and click the Black-point, Mid-point, or White-point Dropper, the mouse
pointer on the preview image changes...

Adjusting Tone CurveYou can adjust the brightness of an image by selecting the type of graph (tone curve) showing the balance
of tone input and output, via 
 (Tone Curve Settings) in ScanGear (scanner driver)'s  Advanced Mode
tab.
Note