Die Lines and Cut Contours: From Kiss-Cut to Through-Cut

Die lines (also called cut contours, die-cut paths, or cutting dies) are vector paths embedded in a PDF that define the shape and position of cuts, creases, and perforations on a printed sheet. They tell the die-cutting machine exactly where to cut, score, or perforate the paper — and they tell the imposition software how to position artwork relative to the die.

Die lines are essential for any project that involves non-rectangular cutting: stickers, labels, packaging, pocket folders, pop-up cards, and any printed piece that is cut to a custom shape. Without a die line, the die-cutting operator has no reference for where to place the cutting rule, and the imposition software has no reference for positioning bleed and artwork.

In PDF, die lines are vector paths assigned to a spot color that prints on a separate plate. This ensures the die line appears on its own separation — the die-cutting operator uses this separation to make the cutting rule. The die line must not print on the CMYK plates because it would appear as a visible line in the finished product.

PDF Press detects die lines automatically by their spot color name and uses them for nesting, step-and-repeat, and bleed calculations. The die line is preserved on its own plate in the separated output.

Die-cutting comes in two fundamental types, and each has different die line requirements:

Kiss-cut: The cutting blade penetrates the top layer (face stock) but not the backing layer (liner). Common for stickers, labels, and any product that stays on a backing sheet after cutting. The kiss-cut line defines the outline of each individual sticker, cutting through the printed material but leaving the backing intact so the stickers can be peeled off individually.

Kiss-cut characteristics:

• Cut depth: through face stock only, not through the liner
• Die line type: closed path around each sticker shape
• Minimum gap between kiss-cuts: 1.5–2 mm (to prevent tearing between adjacent stickers)
• Typical products: bumper stickers, product labels, sheet stickers, vinyl decals

Through-cut (also called pop-cut or butt-cut): The cutting blade penetrates all layers — face stock, adhesive, and liner. This separates the printed piece entirely from the surrounding sheet. Through-cut is used for business cards, hang tags, coasters, and any product that is a standalone piece after cutting.

Through-cut characteristics:

• Cut depth: through all layers (face stock + adhesive + liner)
• Die line type: closed path around each piece, with bleed outside the path
• Minimum gap between through-cuts: 2–3 mm (slightly larger than kiss-cut because of blade width and cutting tolerance)
• Typical products: business cards, hang tags, coasters, door hangers

Many sticker and label products use both kiss-cut and through-cut on the same sheet: kiss-cut around each individual sticker, and through-cut around the perimeter of the entire sheet. This requires two separate die lines on two separate spot-color layers.

In PDF Press, you can assign different spot colors to each die line type (e.g., "KissCut" for kiss-cuts and "ThruCut" for through-cuts), and the engine will separate them onto different plates for the die-maker.

Die lines must be assigned to a spot color with a specific name so that the die-cutting operator can identify the cutting, creasing, and perforation paths. Industry-standard naming conventions include:

• CutContour (or CutContour1, Cut1): The primary through-cut path. This is the most commonly used name in packaging and label production.
• KissCut (or KissCut1, Kiss1): The kiss-cut path for stickers and labels.
• ThruCut (or ThruCut1, Thru1): A second through-cut path, used when a sheet has both a perimeter cut and interior cuts (e.g., a sticker sheet with kiss-cuts for each sticker and a through-cut for the sheet outline).
• Crease (or Score, Fold): The creasing/scoring path for fold lines. Typically rendered as a dashed line on the die.
• Perf (or Perforation): The perforation path for tear-off sections. Rendered as a dotted line on the die.
• Regist: The registration path, used for aligning the die to the printed image.

Spot color attributes for die lines:

• Color type: Spot (not process CMYK)
• Color appearance: Any visible color (Magenta 100% is common for visibility in proofs)
• Overprint: ON — the die line should overprint the artwork beneath it, not knock out
• Halftone: 100% solid — no screens or tints on the die line
• Stroke weight: Hairline (0.25 pt or less) for cutting paths, 0.5–1.0 pt dashed for crease paths

Why overprint matters: If the die line is set to knockout, it will create a white gap around the cut path in the final print — exactly where you need bleed coverage. Setting the die line to overprint ensures it prints on top of the artwork without removing any ink, preserving full bleed coverage up to and beyond the cut line.

PDF Press recognizes all standard die line spot colors and preserves them on their own plate in the separated output. You can also define custom spot color names in the imposition settings.

The geometry of a die line has production implications that go beyond aesthetics. A few key considerations:

Corner radius: Every corner on a die-cut shape has a radius — even "sharp" 90° corners have a minimum radius determined by the cutting blade width. Steel rule die blades are 0.71 mm (2 pt) thick, which means the minimum inside corner radius is approximately 0.35 mm. Outside corners can be sharper (down to 0.1 mm) because the blade wraps around the corner.

For kiss-cut stickers, common corner radii are:

• 0 mm (square corners) — possible but not recommended for stickers because the corners tend to lift and peel
• 1 mm — minimum recommended for kiss-cut stickers
• 2 mm — most common for product labels
• 3–5 mm — standard for rounded stickers and business cards
• 6+ mm — large-radius corners for "pill" and "capsule" shapes

Path closure: Every cut path must be a closed path — an open path will not produce a complete cut. Verify that all die line paths are closed before sending the file to the die-maker. PDF Press automatically checks for open paths and warns you if any die lines are unclosed.

Path direction: The direction of a closed path (clockwise or counterclockwise) determines which side is the "inside" and which is the "outside" of the cut. Most die-making software follows the convention that counterclockwise paths are cuts and clockwise paths are relief cuts (holes). If the direction is wrong, the die will cut the wrong side of the line.

Node count: Die lines should have the minimum number of nodes (anchor points) needed to define the shape. Excessive nodes (from auto-tracing or excessive manual editing) create jagged cuts and increase die-making costs. Simplify paths to the fewest nodes possible while maintaining the desired shape.

Not all die lines are solid cuts. Crease (score) lines and perforation lines use dashed patterns to indicate where the paper should be folded or partially cut:

Crease lines: A crease (or score) is a depression pressed into the paper that creates a designated fold line. In die-making, the creasing rule has a rounded top (not sharp) that compresses the paper fibers without cutting them. On the die line, crease paths are drawn as dashed lines with a specific dash pattern:

• Standard crease dash pattern: 6 mm dash, 2 mm gap (3:1 ratio)
• Heavy crease (for thick card): 8 mm dash, 2 mm gap (4:1 ratio)
• Micro-crease (for thin paper): 4 mm dash, 1 mm gap (4:1 ratio)

The dash pattern is critical because the die-maker converts each dash into a creasing rule on the die. If the dashes are too short, the creasing surface is too small and the paper may not fold cleanly. If the gaps are too long, the fold line has gaps where the paper can still crack.

Perforation lines: A perforation is a series of small cuts that allow the paper to be torn along a designated line. On the die line, perf paths are drawn as very short, closely-spaced dashes:

• Standard perf: 2 mm cut, 1 mm tie (2:1 ratio)
• Easy-tear perf: 3 mm cut, 1 mm tie (3:1 ratio)
• Micro-perf: 0.5 mm cut, 0.5 mm tie (1:1 ratio) — used for clean-tear coupons and reply cards

Mixed cut-and-crease lines: Some die lines combine cutting and creasing on the same path. For example, a pocket folder might have a solid through-cut line around the perimeter and a dashed crease line for the pocket fold. These are drawn as two separate paths on two separate spot-color layers, even if they follow the same geometric path.

In PDF Press, you can set the dash pattern for each die line individually. The engine supports solid (for cuts), dashed (for creases), and dotted (for perforations) stroke styles, each assigned to its own spot color for plate separation.

The stroke weight of a die line determines how the die-maker interprets it. Standard thickness conventions are:

• Hairline (0.125–0.25 pt / 0.04–0.09 mm): Used for cutting paths (through-cut and kiss-cut). The thin line ensures precise die-making with minimal offset between the path and the cutting edge.
• 0.5 pt (0.18 mm): Used for crease/score paths. The slightly heavier line helps the die-maker distinguish creases from cuts on the same design.
• 1.0 pt (0.35 mm): Used for perforation paths and fold lines that need to be visible in proofs.
• 2.0 pt+ (0.7 mm+): Used for reference lines, bounding boxes, and locator marks that don't correspond to physical cutting rules.

Why hairline matters for cutting paths: The die-making process transfers the PDF path to a steel rule using a laser or a manual bending process. If the die line is too thick, the die-cutting blade follows the center of the line, but there's ambiguity about whether the cut should be on the inside edge, outside edge, or center of the stroke. A hairline path eliminates this ambiguity — the blade follows the exact path with zero offset.

Bleed allowance for die lines: All artwork must extend beyond the die line by at least 1–3 mm (bleed) to account for cutting tolerance. The die line itself is the trim boundary, and any artwork that stops at the die line will show a white edge on the finished piece if the cut is even slightly misaligned.

PDF Press enforces hairline (0.25 pt) stroke weight for cutting paths and provides dash settings for crease and perf paths. The engine also calculates and displays the bleed zone around each die line, showing whether your artwork extends far enough beyond the cut line.

PDF Press provides comprehensive die line support throughout the imposition workflow:

1. Die line detection: On import, PDF Press automatically detects vector paths assigned to standard die line spot colors (CutContour, KissCut, ThruCut, Crease, Perf, and custom names). Detected die lines are highlighted in the preview.
2. Die line editing: The built-in vector editor lets you modify die line paths — add nodes, adjust corner radii, close open paths, and change path direction. You can also create new die lines from scratch.
3. Nesting with die lines: When using the nesting engine, PDF Press uses the die line paths as the nesting boundary rather than the bounding box. This ensures true-shape nesting for irregular stickers.
4. Bleed calculation: The engine calculates the bleed zone around each die line based on your bleed settings (default: 2 mm). It verifies that artwork extends beyond the bleed zone and warns you if any areas lack sufficient bleed.
5. Plate separation: When exporting color separations, PDF Press assigns each die line spot color to its own plate. The KissCut plate, ThruCut plate, and CMYK plates are output as separate PDFs for the printer and die-maker.
6. Die line visibility in proofs: You can toggle die line visibility on and off in the proof PDF. For client proofs, show the die line in Magenta at 0.5 pt weight. For production files, set the die line to overprint hairline on its own spot-color layer.

With automatic die line detection, true-shape nesting, and spot-color plate separation, PDF Press handles the complete die line workflow from import to production-ready output.