A blank line that feels modest in a manuscript can consume most of a small reading screen after the reader enlarges the type. Removing every blank line is not a safe answer either, because some gaps carry editorial meaning: they tell the reader that time, place, or point of view has changed. The practical way to handle blank lines in EPUB is to separate routine paragraph spacing from intentional scene breaks, then verify both the package structure and the rendered result.
Classify the Gap Before Changing It
Work on a copy and review every gap with its surrounding sentences. Mark ordinary paragraph boundaries in one category and scene transitions in another. Repeated space between all paragraphs usually belongs to a style rule. A gap used only when the narrative jumps to another time or location is a semantic transition and needs a durable signal.
Write the decision before adjusting the source. A useful row records the chapter, preceding sentence, following sentence, role of the gap, and chosen representation. This prevents a reviewer from keeping gaps that happen to look attractive in one viewport while deleting equally meaningful transitions elsewhere.
Do not use a single visual rule for dialogue, exposition, and scene changes. A new speaker normally needs a new paragraph, not an extra empty paragraph. A substantial shift may need a scene-break marker or a dedicated class. The manuscript should explain why the separation exists even before CSS controls how wide it appears.
Put Routine Paragraph Space in the Stylesheet
Ordinary paragraph rhythm should be expressed through a consistent output style rather than empty paragraph elements. In the fixed four-chapter test for this article, the generated CSS contained a paragraph-spacing rule. The OPF also carried the test title, creator, publisher, and ja language value. Package inspection found seven spine items, four navigation links, and zero missing resources, and Rune’s local inspection returned valid=true.
Those observations establish that the rule and expected package components were present in that synthetic EPUB. They do not establish a universally ideal amount of space. Reflowable books respond to reader font settings, line spacing, margins, and screen width, so a value that looks restrained on a laptop may feel excessive on a phone.
Keep source structure simple: one paragraph boundary between paragraphs and no stack of empty elements added merely to push text downward. If the desired rhythm changes, adjust the declared paragraph style, export a new package, and compare representative chapters. A style-level decision is easier to audit and reverse than dozens of manual gaps.
Give Scene Changes a Meaningful Signal
An empty-looking gap can disappear at a page boundary. A reader who lands at the top of the next virtual page may not realize that the narrative has shifted. Depending on the book’s editorial design, use a short separator, an accessible scene-break element, or another consistent structural marker instead of relying on vertical distance alone.
Avoid multiplying blank paragraphs around that marker. The source should contain one intentional break; presentation rules can provide the surrounding space. Test the marker in the middle of a page, near the bottom, and immediately after a chapter heading. The same treatment can become redundant at a chapter opening, so document any exception rather than applying it silently.
If a decorative character is used, consider how it will sound in text-to-speech and whether it pollutes search results. A purely visual ornament may need an accessibility treatment. The exact solution depends on the production system, but the acceptance question remains stable: can a reader perceive the transition when the page boundary and font size change?
Inspect Several Viewports, Not One Favorite Screen
Open the exported EPUB at a normal type size, a larger accessibility size, and a smaller size. Check portrait and landscape orientations when the target reader supports them. The pass condition is not a fixed measurement in pixels. Routine paragraphs should remain connected enough to read as continuous prose, while scene transitions should remain distinguishable from ordinary paragraph flow.
The deterministic evidence recorded for this article did not measure perceived blank-space size across reader devices. That is deliberately left as a visual review item. Record the reader name and version, device or viewport, type size, orientation, chapter, and observed result. Do not convert a local package pass into a claim about every reading system.
At least one specimen should cross a virtual page boundary. If a scene break loses its meaning there, revise the structural marker rather than adding more empty lines until one screenshot looks satisfactory. Repeat the same specimens after every global spacing change, because a correction for one chapter can alter all other paragraphs.
Trace an Oversized Gap Back to Its Source
When a nearly empty screen appears, first inspect the manuscript for consecutive blank paragraphs. Next check whether routine paragraph margin and scene-break margin are both applied to the same element. Also look for a forced page break adjacent to the scene break; the combination can create far more space than either rule alone.
Make the correction in the authoritative manuscript or export configuration. Editing the generated XHTML may produce a convincing one-off file, but the correction will disappear at the next export. Save the repaired EPUB under a new name and preserve its hash so reviewers cannot unknowingly reopen the older package.
After removing accidental blanks, confirm that two paragraphs were not merged. In Markdown-oriented workflows, a blank source line often defines a paragraph boundary. The aim is to remove empty content, not the structural separation between real paragraphs. Inspect the resulting XHTML around each corrected specimen.
Keep Package Validity Separate From Editorial Quality
The fixed package’s valid=true result is a local structural result. It is not retailer acceptance, a literary judgment, or proof that every reading app produces identical spacing. Conversely, a visually pleasing page can still contain a broken navigation link or missing resource. Give package checks and reading checks separate decisions.
The seven spine items in the test package include more than the four manuscript chapters. Review each item’s role instead of assuming that chapter count and spine count must match. Confirm that the four navigation links reach the intended four chapters and that the OPF metadata matches the publication plan. None of these structural checks replaces reading the transitions.
When a retailer or distribution platform is part of the handoff, run its current acceptance process separately. Preserve that result with the exact uploaded file. A later export, even from unchanged prose, is a different package and needs a new structural and visual check.
Hand Off the Rule, Exceptions, and Evidence
The final record should state the routine paragraph rule, the scene-break representation, documented chapter-opening exceptions, tested readers, and the EPUB hash. For this controlled package, the evidence supports the presence of the spacing rule, seven spine items, four navigation links, zero missing resources, and a successful local inspection.
List device-specific spacing as unmeasured until a person completes the visual matrix. A future editor deciding whether to add a gap should first identify its function. Store meaning in the manuscript structure and presentation distance in the stylesheet. That distinction keeps the book readable when font size and viewport change, and it gives the next production pass a clear place to diagnose any empty screen.