This function allows you to straighten pages that were skewed when the original document was scanned.

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Straightening skewed documents is possible only if the original type is Image PDF (
). Additionally, automatic straightening is possible only if the document’s color mode is black and white (1 bit)(
).
If you perform other edits on a document that has been straightened and then perform straightening again, the image quality might deteriorate. (If you are only straightening a document, the image quality will not deteriorate no matter how many times you perform straightening.)
This function can be performed using the on-screen items indicated in the following illustration.
Note that this explanation outlines general use of the settings area. For details about a specific setting, see the on-screen balloon help that appears when you click the
button.

, the [Deskew] button
Click this to adjust the image’s skew.
Settings area
When you click
, the [Deskew] button, the settings for adjusting the degree of the document's skew will appear here.
In the thumbnail area, select the page that you want to de-skew, specify each setting, and then click [Apply].
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If you are straightening the skew manually, reference lines are displayed on the page. You can move these reference lines with the mouse. Also, dragging a point (
) on the reference line lets you freely correct the skew angle.
