Thin White Lines in a Logo PDF: Separate Stitching From Real Gaps

A thin white line between adjacent logo colors can be a display seam, a consequence of transparency processing, or an actual gap in the artwork. Check the same PDF at different zoom levels and in another viewer, inspect the editable source, then confirm the intended print output with the printer.

Do not redraw the logo from a screenshot or assume the line is harmless because it disappears at one zoom level. Those observations help locate the problem; they do not approve the production file.

Understand what stitching means

Adobe documents thin white or dark lines in PDFs exported from InDesign, including cases involving transparency flattening and older compatibility settings. Its explanation also identifies display smoothing as a possible source of visible seams. PDF 1.3 does not support transparency, so InDesign flattens transparency when exporting to that compatibility level. Adobe's stitching guidance describes these conditions.

That guidance concerns particular processing and display behavior. It does not establish the cause of every white line in every logo PDF. Your job is to determine whether the line belongs to the source artwork, appears during export, or arises when the resulting file is displayed or printed.

Compare the same file before editing

Preserve the source and original PDF. Make a short observation record:

1. Note the PDF filename, affected page and precise location of the seam.
2. View that location at several zoom levels, recording when the line appears or disappears.
3. Open the identical PDF in another viewer and compare the same area.
4. In Acrobat, if available in your version, compare the display with Smooth Line Art enabled and disabled under Page Display preferences.
5. Return to the original display setting after recording the result.

Adobe includes the smoothing comparison in its troubleshooting instructions. Changing that preference alters the viewing condition; it does not repair the PDF or demonstrate what a printer will produce.

For screen delivery, also check the viewing environment your audience will use. A file that looks acceptable only after a specialist preference change may still be unsuitable for that audience.

Use observations to choose the next check

The following examples are hypothetical. They illustrate a decision process, not performed tests or confirmed diagnoses.

Source artwork	PDF observation	What to investigate next
Adjacent shapes appear joined	Hairline changes with zoom and smoothing	Viewer rendering and export processing
Visible separation exists between paths	Gap remains at the same location	Source geometry and intended design
Source appears correct	Line follows an area using transparency	Compatibility and transparency handling
Source and screen PDF look correct	Line appears on a physical proof	Printer processing and the exact proof file

Suppose a hypothetical two-color symbol looks joined in the editor, but a hairline appears at 125% zoom and vanishes at 200%. That supports further display investigation. It does not justify the statement “this will never print.” Record the observation and send the file for output checking.

If the symptom is an entire white object disappearing, use the white-logo overprint guide instead. If the visible defect is a series of steps through a gradient rather than a seam between regions, consult the logo gradient banding guide. Naming the symptom accurately prevents unrelated fixes.

Inspect geometry and export settings separately

Ask the designer to inspect the actual neighboring paths, clipping and any unexpected strokes in the editable master. A screenshot cannot show whether two shapes truly meet. Where the artwork contains an unintended gap, correct that specific geometry on a copy and compare it with the approved logo.

Avoid adding overlap to every shape merely to hide screen lines. First establish where a gap exists and whether any proposed change alters the mark's intended edges or color relationships.

Next, record the export preset and PDF compatibility. Adobe's InDesign guidance includes comparing PDF 1.4 or later for the described older-compatibility issue. Ask the printer which specification its workflow accepts before changing the production preset. Neither a newer compatibility level nor PDF/X-4 is automatically the right delivery for every printer.

Keep a candidate export under a separate filename. Compare it with the original using the same viewers, zoom levels and output size. Do not simultaneously change compatibility, colors and artwork geometry: a better-looking result would then be difficult to explain or reproduce.

Use the agreed proof to decide print acceptance

Send the printer the actual candidate PDF, not only the screenshot that shows the seam. Ask for review of the marked area using the agreed production workflow and a suitable proof. Include the intended logo size and background.

An office print can be useful as an observation, but it does not establish the result on another device, material or production process. The logo print-proof guide helps organize that approval separately from your screen comparison.

Do not rasterize the entire delivery solely because a preview contains a line. If the printer proposes a rasterized alternative, agree on the output requirements and inspect the resulting logo detail before acceptance. Keep the editable master regardless of the final delivery format.

Keep a focused handoff record

Package the master, original PDF and candidate PDF with:

• One annotated screenshot identifying the seam.
• Viewer names, versions, zoom levels and smoothing observations.
• Export preset and compatibility for each candidate.
• Intended output dimensions and the printer's requested specification.
• The proof reviewed and the actual approval decision.

Close the issue only for the deliverable you have checked. A screen seam that disappears is useful evidence; an approved output requires its own review. Keeping those decisions separate protects both the logo's design and the reliability of the handoff.