Tutorial · Stages 1–2 of 6
Split Pages in ScanTailor Advanced: One Page, Part of the Next, or a Two-Page Spread
Before anything can be straightened or cleaned, ScanTailor Advanced has to know what a “page” is in your scans. Stage 1 fixes orientation; Stage 2 decides how each scan divides. Get these two right and the automatic stages downstream behave.
Stage 1: Fix Orientation — Deliberately Manual
Fix Orientation rotates scans in multiples of 90°: sideways scans upright, upside-down scans the right way up. That is all it does — the fine angle correction comes later, at Deskew.
This stage is manual on purpose. As the project documentation puts it, the program cannot determine the correct orientation of a scan for you, so batch processing at this stage is pointless: you look, you rotate, you move on. The stage’s panel rotates the current page 90° in either direction and can reset it to its original orientation.
The time-saver is the “Apply to…” dialog, which propagates the rotation you just made:
- This page — the rotation you made is kept (it applies automatically anyway).
- All pages — when a whole scanning session came out rotated the same way.
- This page and the following ones — when orientation changes part-way through the book.
- Every other page — the classic book-scanning pattern: alternating left/right pages shot from a fixed rig often alternate orientation. The option respects whether the current page is even or odd.
- Selected pages / every other selected page — available when you have selected two or more pages in the thumbnails panel (use Shift+click for a continuous run).
v1.2.0 added a small mercy for camera work: manual per-image trim at this stage, so an obviously oversized capture can be trimmed before it confuses later stages.
Stage 2: Split Pages — Three Scan Types
Split Pages decides how each scan is divided. The program distinguishes three situations, shown in the stage’s panel as the type of division:
1 · Single page, complete
The scan holds one whole page and nothing of the next. Typical of flatbed scans, dedicated book scanners, and one-page-at-a-time camera work.
2 · Single page plus part of the next
The scan is mainly one page, but a strip of the neighbouring page crept in — common when an open book overhangs the capture area.
3 · Two-page spread (twin scan)
The scan holds a full open spread: left and right pages together, to be cut into two pages at the dividing line near the spine.
The type is detected automatically and can be corrected manually with the stage’s “Change…” control. Like orientation, the chosen type can be applied to all pages at once — but check the detection on a sample first, because a book scanned as spreads that gets treated as single pages (or the reverse) produces garbage at every later stage.
The dividing line
For spreads and partial-overlap scans there is a dividing line — the cut position. It is also placed automatically and can be dragged manually per page. One asymmetry to remember: the dividing line cannot be applied to other pages. Every spread’s spine sits slightly differently, so the line is a per-page setting; the type of division is the project-wide one.
ScanTailor Advanced reworked this stage’s “apply cut” behaviour compared with the classic version: when a cut is applied to pages whose dimensions differ slightly from the page it was made on, the program now adapts the cutters to those pages instead of rejecting the setting outright and falling back to automatic mode — and in manual mode it validates cuts and rejects settings that would produce an invalid page layout.
The Two-Page Spread Caution: Order Is Everything
Related housekeeping:
- Right-to-left books: v1.2.1 added an explicit “reverse two-page spread order” fix for Japanese and other right-to-left workflows, where the right page of a spread is read first. If you scan RTL material, look for that option rather than renumbering files by hand.
- Front/back matter: covers, fold-outs and plates are often single pages inside a spread-scanned book. Set their type individually — don’t let a project-wide “twin scan” rule cut a plate in half.
- Spot-check the preview strip. The project wiki’s advice is to flip through the preview of each page and confirm the split landed correctly; illustrations crossing the gutter are the classic case that fools the automatic line placement.
Two capture habits that make splitting reliable
- Single-page scans: shoot portrait, not landscape. The documentation recommends portrait orientation for one-page captures — it materially improves automatic detection of both the division type and the line.
- Capture raw. Choose the mode in which the scanner or camera software does the least “improving” and compressing. Pre-processed scans (auto-cropped, auto-enhanced) are the ones the automatic split gets wrong. More in the DPI and capture guide and the hardware guide.
Frequently Asked Questions
Why can’t ScanTailor detect page orientation automatically?
By design. Fix Orientation is a manual stage because the program has no reliable way to know which way up a scan should be. You rotate in 90° steps, and the Apply to dialog propagates your decision to all pages, the following pages, every other page, or a selection — which is how a whole book gets oriented in a few clicks.
Can I apply the dividing line from one spread to the whole book?
No — and that is deliberate. The type of division (single, partial overlap, twin scan) applies project-wide, but the dividing line is per page, because every spread’s spine position differs slightly. Drag it on the pages where the automatic placement is off, and spot-check the previews.
My two-page spreads came out in the wrong order. What happened?
A split spread yields a left and a right page; for left-to-right books the left comes first. Wrong pair order usually means the split direction or capture order was flipped. For right-to-left books, v1.2.1 explicitly supports reversing two-page spread order — use that instead of renaming files manually.