A document feeder that scans both sides is fast, but it records every side it sees. A stack of single-sided letters becomes a PDF with a blank page after each real one. A pile with separator sheets, or a report with intentionally empty pages, adds more. The result is a file that is twice as long as it should be, harder to read and, for many portals, larger than allowed. This guide explains why the blanks appear, why automatic removal on the scanner is risky, and how to remove the blank pages afterwards while checking each decision.
Why blank pages appear
Scanners with automatic document feeders can capture both faces of a sheet in one pass. ScanSnap's help says of its models that "you can scan both sides of a document", by choosing "[Duplex] for [Scanning side]" in the scan settings. If the back of a sheet is empty, the scanner still produces an image of it. Three situations cause most blank pages:
- Single-sided originals scanned in duplex mode. Every real page is followed by an empty back.
- Separator sheets. Blank sheets placed between documents to split a batch.
- Pages left blank on purpose. Some printed reports and booklets include them.
A fourth case is marks showing through. Epson's Epson Scan 2 help refers to the scanner detecting "marks from the other side of a blank page" and tells you to adjust the Skip Blank Pages setting to stop them appearing in the scan. A back that is empty to the eye can still carry faint show-through from the front.
The risk of letting the scanner delete blanks
Most scanner software has a switch for removing blank pages while scanning. It is convenient, but the vendors themselves warn about it. A ScanSnap help article, titled "Scanned Pages Are Sometimes Unexpectedly Detected as Blank and Not Saved", says that documents including white pages with very little text and solid-colour pages may be detected as blank when the [Blank page removal] option is selected. Its advice is to turn the option off and to check the scanned images against the originals so that no page is lost by mistake. Another ScanSnap page notes that "the pages which are almost blank may be detected as blank pages and deleted" and that enabling the Reduce bleed-through option can cause more documents to be detected as blank.
The consequence is plain. A page with one line, a signature, an initial or a stamp can be dropped without any message in the saved file. For a contract, an application or a medical record, a missing page can matter more than an extra blank one. The safer order is to scan everything, then remove blanks from the PDF with the pages in front of you.
How DocPro finds blank pages
Remove blank pages renders each page as a small thumbnail and measures how much of it is not white, ignoring a thin border where scanner edges and punch holes show. It lists that share as "ink" for each page. A page counts as blank when its ink share is at or below a limit you control. You then confirm or override every page before anything is removed. The file is processed in your browser and is not uploaded.
How to remove blank pages with DocPro
- Open Remove blank pages and choose the scanned PDF. A progress line shows "Looking at pages" while the thumbnails are made.
- Look at Blank page sensitivity (maximum % of page covered by ink). It runs from 0 to 5 percent and starts at 0.3 percent. The line under it says how many blank pages were found and how many stay.
- Raise the sensitivity if backs with scanner noise or a faint edge shadow were not flagged. Lower it if pages that carry only a footer or a page number were flagged.
- Check the thumbnail grid. Each page shows its number and an INK value, and a tick box. Ticked pages are labelled Remove and the rest Keep. Tick or untick any page to override the automatic choice.
- Press Remove selected pages. The result card reads "Removed N blank pages" with the number of pages left, and the new file is named like the original with "no-blanks" added.
At least one page must stay, so the tool refuses to remove every page. The button is disabled when nothing is selected.
Pages to look at twice
- Pages with only a signature, initials or a stamp. These have a low ink value and are the pages most likely to be flagged at a high sensitivity.
- Pages with only a page number or footer. The same applies.
- Pages that say they are left blank on purpose. Keep them if a form or the page numbering depends on the count.
- Very pale originals. A light grey form or a faint pencil note can look blank to a threshold. Look at the thumbnail, not just the ink number.
A good habit is to scroll the full thumbnail grid once before pressing the button and to open the saved PDF afterwards to confirm that the page count matches what you expected.
After removing the blanks
- Pages in the wrong order: use Organize PDF to rearrange them.
- Several scans that belong together: Merge PDFs joins them into one file.
- A file still above a portal's limit: Compress PDF can reduce it, and the guide to what DPI to scan at explains how to scan once and shrink later.
- A single unwanted page that is not blank: the task page for deleting pages from a PDF removes it by number.
- Searchable text: OCR to PDF adds a text layer, see the guide on making a scanned PDF searchable.
If the scans are photos taken with a phone, Images to PDF builds one PDF first, and Remove blank pages then works on that PDF.
What DocPro cannot do
The tool judges a page only by how much of it is not white. It does not read text, so it cannot tell a page that says "intentionally blank" from an empty one. It accepts PDF files, not loose images. It does not reorder pages or fix a stack that was fed in the wrong order. It cannot change your scanner's settings. If the scanner already deleted a page, that page is not in the PDF and cannot be recovered from it, so rescan from the paper.
Frequently asked questions
Why does my duplex scan have blank pages?
A duplex scan captures both sides of every sheet. If the back of a sheet is empty, the scanner still saves an image of it. Single-sided originals, separator sheets and pages left blank on purpose all produce blank pages.
Is it safe to let my scanner remove blank pages automatically?
Use caution. ScanSnap's help pages warn that white pages with very little text can be detected as blank and not saved, and advise checking the scanned images against the originals. Scanning everything and removing blanks afterwards lets you review each page.
How does DocPro decide a page is blank?
It renders each page and measures the share that is not near-white, ignoring a thin border. Pages at or below the sensitivity you set are flagged, and you can tick or untick any page before removing.
Will it remove a page with just a page number or signature?
It might, depending on the sensitivity. Pages with a small amount of content can be flagged, so review the thumbnails and untick any page that matters before you press the button.
Is my scan uploaded?
No. Remove blank pages analyses the PDF in your browser and the file stays on your device.