Free Online Pdf Deskew
Online Pdf Deskew

I don’t know whether this happens to you, but it surely does to me! I scan a document into my Mac either using one of my multifunction printers or my Brother Document Scanner. About 50% of the time, the PDF document scans crooked, it is skewed one way or the other. So then I scan it a few more times until I get it right. There are other ways to deal with scanned PDF files that are skewed.

Unskewing The Skew

The most powerful feature is its ability to query back-ends for scanner specific options which can be set by the user as a scanner profile. It also has support for authentication, mutlicast DNS discovery, simultaneous scan jobs, image transformation jobs (deskew, binarize, crop, etc), PDF and PNG output. It can also be integrated with your own. A-PDF Deskew provides a quick way to correct the skew scanned image in Acrobat PDF documents directly. It detects tilt images and straightens them automatically. A-PDF Deskews features include processing a batch of PDF file, even working with password protected files, filtering small images which may be a logo or else and dealing out some page.

Deskew is a tool for deskewing scanned text documents. Deskewing is a term used for fixing the scans to get the lines of text straight. That means rotating the image of the scanned page a little to compensate for the misalignment of the paper in the scanner. You can save as PDF/A, remove artefacts and noise, deskew pages, set meta information and join to a single output file. Easy to use PDF24 makes it as easy as possible for you to recognize text via OCR. The Online OCR service will automatically detect such pages and preprocess them to straighten them before the OCR process. Creates Searchable PDFs Free Online OCR creates PDF files where the text information is inserted in a separate invisible layer, making it possible for you to search and index the file.

I have done tons of research on this problem using my own Apps and online as well. I tried to find ways to fix skewed PDF files that would not cost people much money. The first place I looked was the macOS Photos App. Here is a typical skewed PDF file that is opened in the Editing area of the Photos App:

The way to remove the skew is to go into the Crop mode. Once you are in Crop you can use the adjusting wheel to straighten the image slowly:

This works pretty well with one caveat. When you use the Crop feature in the Photos App, you do lose some of the edges of your photo or document. That is no big deal. If your PDF has decent edge margins you won’t even notice it.

Some Apps have a Deskew feature. Here is the setting in PDFPen Pro: John deere e100 mower user%27s manual.

This Deskew feature usually works in conjunction with some type of OCR capability. PDFPen Pro imports the document and asks if you wish to OCR it. If you say yes, the document is OCR’d and straightened at the same time. If you just drag a already scanned PDF file into PDFPen Pro you can still Deskew it if you access the “Deskew and Adjust Image” command in the Edit menu:

So, why not just use PDFPen Pro you ask? Because PDFPen Pro is expensive. There is no better App out there if you do much work with PDF files. If you only need an occasional Deskewing, you might just stick with the Photos App.

I found this PDFScanner App in the App Store by doing a search on PDF OCR. It gets good reviews and it appears to correct skewed documents automatically on scan or manually later. I did not wish to invest $14.99 to confirm all this, but it does seem to get good reviews. If you need OCR and skew repair capability you might give it a try. It does not do as much as PDFPen Pro, but it would be adequate for many people.

Here is something to think about. When I had bought my Brother Document Scanner it came with PageManager software which does have a Deskewing feature. Along these lines, if you have a multifunction printer, it probably has some type of scanning software available. The HP Easy Scan software that came with my HP OfficeJet Pro 8610 has a “Straightening” feature:

Once you have the document or photo scanned into the HP Easy Scan software you can access the Straightening feature in the Edit window. It is somewhat crude, but it works with some patience.

You can find some services on the Web that advertise Deskewing documents, but I thought they were pretty crude. I am sure Photoshop and other expensive editing programs have Deskewing capabilities, but who wants to pay for it.

I even downloaded the Adobe Acrobat Reader App to see if it had some type of Deskewing feature, but no joy. Of course, you can always buy Acrobat Professional for a few hundred dollars, but who can afford that. Is khaki the same as beige.

If you know of any free or inexpensive software that can Deskew a scanned PDF document please let me know in the Comments Section and I will review it.

Free Online Pdf Deskew

Conclusion

If you are like me, you have need of Deskewing services from time to time. There are always the Photos App or your multifunction printer software if you wish to keep it in the realm of FREE. If you are willing to invest some dinero, there are other solutions that work very well.

One of the most common problems with scanned pages is that they are are skewed by a couple degrees, which can be annoying and unpleasant to the viewer. It can also cause problems with processes such as Optical Character Recognition (OCR). Many times these processes attempt to manually correct those scans by rotating them backwards (deskewing them), but that's not always successful or even possible (for example with non-scanned documents). So how to solve this problem?
Well, with this new tool you can easily deskew some, or all, the pages of a PDF file, in either an automatic or a manual process.
Let's have a look at an example: This is our original file with skewed pages that we want to rotate.
Notice the script is installed and available under Tools - Add-On Tools.

The original first page of the file (click to enlarge)
So how do we do it? We use the Line commenting tool to draw a line that represents the angle in which we want to rotate the page. So if there's a table on the page, for example, that line should be parallel to its top border:

Online Pdf Deskew

The skewed page with the line we added to itAfter adding the line we select it (multiple lines on multiple pages can be selected at once in the Comments List panel). We then run the script and in the Properties dialog select to use the 'Selected Annotations' option.
If we want we can also select to remove these lines after the pages are processed.

The script's properties dialog And the result is..

First page after automatic deskewingAs you can see, the result is pretty good: The page is much straighter now.
We can find out by how many degrees (clockwise) it was rotated by opening the JS Console (Ctrl+J):

The automatic rotation angle for page #1.
(Although the value is a fraction, in fact the rotation is in whole degrees only)
Now lets say we want to specify ourselves by how many degrees to rotate the page.
We take page #2 of the same document and run the script once more..

The original page #2 This time in the Properties dialog we select to process the current page only and enter the degrees manually as '-2' (since we want to rotate it counter-clockwise):

And the results look pretty good once again:

We can now process the rest of the pages using the same setting, if we wish.
Important note: This process will NOT affect objects on the page such as form fields, annotations, links, etc. They will all remain in tact.