How to Use Overlap Settings for Seamless Poster Assembly
This guide is for anyone printing images across multiple pages and struggling with cutting and alignment. PrintTiler's overlap feature adds duplicate content at page boundaries, making it easier to align pages perfectly and hide seams when assembling your poster. This guide builds on our techniques for assembling tiled prints with perfect alignment.
In This Guide
What is Overlap?
When you print a large image across multiple pages, each page contains a portion of your image. Without overlap, the pages meet exactly edge-to-edge — any small misalignment during assembly creates visible gaps or mismatched lines.
Overlap solves this by extending each page slightly into the adjacent page's territory. The result: neighboring pages share a small strip of identical content. When you assemble the poster, you can overlay one page on top of the other at this shared zone, ensuring perfect alignment even if your cuts aren't pixel-perfect.
Think of It Like This
Imagine two puzzle pieces that don't just touch at the edges, but actually overlap slightly. You can slide them around to find the perfect fit because you have room to adjust. That's exactly what overlap does for your printed pages.
Why Use Overlap?
Overlap provides several practical benefits when assembling multi-page prints:
Prevents White Gaps
Even with careful cutting, tiny white lines can appear at seams. Overlap eliminates this by giving you extra image content to cover any gaps.
Easier Alignment
With duplicate content on both pages, you can visually match the image elements (lines, colors, text) to achieve perfect alignment before taping.
Forgives Cutting Errors
If your trimming isn't perfectly straight or you cut slightly off the line, the overlap zone gives you margin to work with.
Hides Seams
When one page overlaps another, the seam becomes less visible than a butt joint where edges simply meet.
The Four Overlap Options
PrintTiler offers four overlap settings. The right choice depends on your paper type, cutting precision, and how visible you want seams to be.
Off
0 mm
No overlap. Pages meet exactly edge-to-edge. Best for precise cutting with a paper trimmer and when you want the cleanest possible butt joints.
Use when: You have a precision paper trimmer and plan to use butt joints.
Small
3 mm (0.12")
Minimal overlap. Provides a small safety margin without noticeably increasing page content. Good for thin paper where thick overlaps might show through.
Use when: Using thin paper or when you want minimal visible overlap ridge.
Medium (Default)
5 mm (0.20")
Balanced overlap that works well for most situations. Provides enough margin for alignment while keeping the overlap zone manageable.
Use when: General-purpose poster printing with standard paper.
Large
10 mm (0.39")
Maximum overlap. Gives you the most flexibility during assembly but creates a wider overlap zone. Best when precision cutting isn't possible.
Use when: Cutting by hand with scissors, or for large posters viewed from a distance.
How Overlap Works in PrintTiler
When you enable overlap, PrintTiler extends each tile's crop area into the adjacent tile:
- Right edge: Non-rightmost tiles extend into the tile to their right
- Bottom edge: Non-bottom tiles extend into the tile below them
- Corner tiles: Extend in both directions (right and down)
- Edge tiles: Only extend in applicable directions
Preview Visualization
In PrintTiler's preview, overlap zones are highlighted with a semi-transparent orange color. These orange strips show exactly where duplicate content appears. The content in the orange zone on one page is identical to the adjacent edge of the neighboring page.
What Gets Printed
With overlap enabled, each printed page is slightly larger in content (though the paper size stays the same). The image is scaled down very slightly to fit the additional overlap content onto the page. This scaling is minimal and typically imperceptible.
Without Overlap (Off)
┌─────────────┐┌─────────────┐
│ ││ │
│ Page A ││ Page B │
│ ││ │
└─────────────┘└─────────────┘
↑
Exact seam
(must align perfectly) Pages A and B each contain unique content. Any cutting or alignment error creates a visible gap or mismatch.
With Overlap (5mm)
┌─────────────┬───┐
│ │░░░│← 5mm overlap zone
│ Page A │░░░│ (duplicate content)
│ │░░░│
└─────────────┴───┘
┌─────────────┐
│ │
│ Page B │
│ │
└─────────────┘ Page A's right edge contains 5mm of content that also appears on Page B's left edge. When assembling, place Page A over Page B — the duplicate content ensures alignment even if your cut isn't perfect.
Assembling Pages with Overlap
The assembly technique changes slightly when using overlap:
Arrange Pages
Lay out all pages in order. With overlap, the left and top pages will go "on top of" their right and bottom neighbors at the seams.
Trim the Underlying Page
For the page that goes underneath (right or bottom page), trim off the white margin on the edge that will be overlapped. The overlapping page will cover this edge.
Align Using Visual Markers
Place the overlapping page on top and slide it until the image content matches perfectly. Look for lines, text, or distinctive features that should align.
Secure the Overlap
Once aligned, apply adhesive. Double-sided tape works well for overlap assembly. Apply tape to the back of the overlapping section, then press firmly.
Pro Tip: Work in Rows
For large posters, first assemble all pages in each row (horizontal strips), then join the rows together vertically. This is easier than trying to align everything at once.
Recommended Settings by Situation
Home Inkjet Printer + Office Paper
Medium (5mm)
Standard 80gsm office paper is thin enough that overlap doesn't create a noticeable ridge. 5mm gives good alignment margin for home printing.
Thick Paper / Glossy Photo Paper
Small (3mm) or Off
Thick cardstock or glossy photo paper creates a visible ridge when overlapped. Use smaller overlap or precise butt joints.
Cutting with Scissors (Hand Cutting)
Large (10mm)
Scissors are imprecise for straight cuts. Large overlap gives more room to adjust alignment despite imperfect cuts.
Craft Knife / Paper Trimmer / Guillotine
Small (3mm) or Off
Precision cutting tools like X-Acto knives or rotary trimmers enable accurate butt joints. Minimal or no overlap needed.
Maps, Blueprints & Technical Drawings
Medium (5mm)
Fine lines and text make misalignment very visible. Overlap helps you match the lines precisely across pages.
Large Banners & Wall Posters
Large (10mm)
Seams are less visible from viewing distance. Larger overlap makes assembly faster and easier for big prints.
Quick Reference: Overlap Assembly Checklist
- Overlap setting chosen based on paper type and cutting method
- Orange overlap zones visible in preview
- All pages printed in one batch
- Pages laid out in correct grid order
- Underlying page margins trimmed at overlap edges
- Overlapping pages aligned using visual markers
- Double-sided tape or adhesive applied
- Seams pressed firmly and checked for alignment
Common Questions
Does overlap make my image smaller?
Very slightly. With overlap, each tile contains a bit more image content, so the image is scaled down minimally to fit. At 5mm overlap on A4 paper, this is about 2% — typically unnoticeable.
Can I use overlap with any fit mode?
Yes. Overlap works with No Scale, Fit Width, Fit Height, and Custom Fit modes. The overlap amount is applied after the fit mode calculates the page grid.
What do the orange highlights in the preview mean?
The orange zones show where overlap occurs. Content in these zones appears on two adjacent pages. When you place one page over the other at these zones, the images will match.
Should I always use overlap?
Not necessarily. If you have a precision paper trimmer and want the cleanest possible seams with butt joints, turning overlap off gives you exact edge-to-edge tiles. Most users benefit from at least 3-5mm overlap for easier assembly.
How does overlap interact with the assemble technique?
With overlap, you'll use the "overlap joint" technique rather than "butt joint." See our assembly guide for detailed instructions on both methods.
Ready to Print?
For a complete walkthrough from printing to final assembly, see our step-by-step poster printing guide.
