Guide to perfect folds for brochures, mailers, and print layouts
When you’re designing brochures, greeting cards, or any printed piece that requires folding, it’s crucial to communicate exactly where those folds should occur. Unlike crop marks and bleeds, fold marks aren’t added automatically in Adobe InDesign—you need to create them manually.
In this tutorial, you’ll learn how to set up fold marks in InDesign step by step, so that your printer knows precisely where to fold your layout. This ensures a professional finish and avoids costly production errors.
🧾 What Are Fold Marks?
Fold marks are small lines placed on the edge of a printed document to indicate where it should be folded. These are especially important for:
- Tri-fold brochures
- Z-fold flyers
- Half-fold greeting cards
- Mailers with multiple panels
They do not print on the final product, but they are included in the trim area or slug to assist the printer.
📐 Before You Begin: Set Up the Right Document Size
Make sure your document dimensions match the final flat size (before folding), and consider using guides to plan your fold positions.
For example, a standard US letter tri-fold brochure is:
- Flat size: 8.5″ x 11″
- Panels: 3 vertical sections, each approx. 3.66″ wide (one panel slightly smaller for the fold-in)
Use rulers and guides to mark the fold zones before placing fold marks.
✏️ How to Add Fold Marks in InDesign (Step-by-Step)
✅ Method 1: Manually Drawing Fold Marks
This is the most common method for adding fold marks:
1. Turn on Rulers and Guides
- Go to View > Show Rulers
- Drag guides to your fold positions
2. Draw Fold Mark Lines
- Select the Line Tool ()
- Draw a short vertical or horizontal line (typically 5–6 pt in length)
- Set the Stroke to 0.25 pt (thin) and Black (100% K)
3. Position the Line
- Place the line just outside the trim area (in the bleed or slug zone)
- Duplicate the mark at the top and bottom (or left/right) to indicate the fold across the whole page
4. Group and Lock
- Group your fold marks and consider placing them on a separate layer (e.g., “Print Marks”)
- Lock the layer to prevent accidental changes
✅ Method 2: Add Fold Marks in the Slug Area
The Slug area is ideal for adding fold instructions, especially if you’re working with a print shop that needs production notes.
1. Enable Slug
- Go to File > Document Setup
- Expand the Bleed and Slug section
- Add 0.25″ or 6 mm to all sides
2. Use the Line Tool
- Draw fold marks as above and place them within the slug area, aligned with your fold guides
3. Export with Slug
- When exporting to PDF:
- Check “Include Slug Area” under Marks and Bleeds
💡 Tips for Effective Fold Marks
- Use guides first to plan accurate folds
- Keep marks thin and short—don’t confuse them with crop marks
- Avoid placing marks over design elements or text
- Use a separate layer for fold marks so you can toggle visibility
- Name your marks clearly for print instructions: “Fold Line A,” “Gatefold Center,” etc.
🖨️ How to Export Fold Marks with Your PDF
To ensure your fold marks are visible in the exported PDF:
- Go to File > Export
- Choose Adobe PDF (Print)
- Under Marks and Bleeds, check:
- Crop Marks
- Bleed Marks
- ✅ Include Slug Area (if fold marks are in slug)
- Click Export
This makes sure your printer receives a file with visible fold indicators.
🧠 Alternative: Use Illustrator or PDF Editor for Fold Marks
Some designers prefer to add fold marks in Adobe Illustrator or a PDF editing tool (like Acrobat) after exporting the PDF. This is acceptable for simple jobs, but InDesign offers more control if you build them into your layout.
✅ Final Thoughts
While InDesign doesn’t have a built-in “add fold mark” button, creating fold marks manually is easy and precise once you understand your layout needs. A little extra effort during setup can save big headaches during production.
By using guides, the slug area, and custom lines, you’ll ensure your printed pieces fold exactly where they should, every time.
