Canon PIXMA MG4200 Series On-Screen Manual page 650

Select this to reduce large dust particles and scratches; however, evidence of the reduction process
may remain or delicate parts of the image may be removed.
Important
This function may not be effective for some types of photos.
Note
It is recommended that you select None when scanning printed materials.
Fading Correction
Use this function to correct photos that have faded with time or have a colorcast. "Colorcast" is a
phenomenon where a specific color affects the entire picture due to the weather or ambient strong
colors.
None
Fading correction will not be applied.
Low
Select this to correct a small amount of fading and colorcast.
Medium
It is recommended that you normally select this setting.
High
Select this to correct a large amount of fading and colorcast. This can affect the tone of the image.
Important
You can set Fading Correction after preview.
You can set this setting when Recommended is selected on the Color Settings tab of the
Preferences dialog.
Fading Correction may not be effective if the scan area is too small.
Grain Correction
Use this function to reduce graininess (roughness) in photos taken with high-speed or sensitized film.
None
Graininess will not be reduced.
Low
Select this when the photo is slightly grainy.
Medium
It is recommended that you normally select this setting.
High
Select this when the photo is very grainy. This can affect the gradation and sharpness of the image.
Important
Grain Correction may not be effective if the scan area is too small.
Gutter Shadow Correction
Use this function to correct shadows that appear between pages when scanning open booklets.
When you set the Gutter Shadow Correction setting in the preview image, the result will be reflected.
Preview the effects before scanning, as results vary depending on the type of document and how it is
pressed.
Unclear or blurred text/lines caused by curved pages are not corrected.
None