Minimum Line Weight and Type Size for Every Print Process: Foil, Letterpress, Emboss, UV, CMYK and Die Cut

The short answer: Foil holds positive lines down to 0.1 mm (0.28 pt). We design to 0.15 mm (0.43 pt, 0.006 in) or thicker for the crispest strike, with gaps at 0.25 mm (0.71 pt); the gap floor is 0.15 mm. Letterpress shares those positive-line targets and floors; reversed letterpress lines stay at 0.3 mm. Raised foil and raised spot UV use 0.3 mm (0.85 pt, 0.012 in) line and gap targets, with a 0.17 mm floor. Type sizes, emboss, flat UV and cutting limits are unchanged. The full matrix follows.

The minimums matrix

Find your process, then check the thinnest line in your file against the first column, the narrowest gap or reversed line against the second, and your smallest type against the next two. Registration is how far one layer can land from another, which tells you how tight a fit you can design.

The rest of the minimums

Why targets and floors are different

A minimum tells you what can hold; a target gives the strike room to stay crisp. Our foil and letterpress positive-line floor is 0.1 mm, while 0.15 mm is the design target. Other processes have their own physics.

Paper texture, ink and impression affect the edge you see. We measure detail at final size and preserve the character of the supplied artwork, rather than imposing a heavier version of it.

Hot foil: fine lines and open gaps

Foil holds positive lines down to 0.1 mm (0.28 pt). We design to 0.15 mm (0.43 pt, 0.006 in) or thicker for the crispest strike, with gaps at 0.25 mm (0.71 pt); the gap floor is 0.15 mm.

A heated die presses foil film against the sheet. Foil releases from its carrier where the die touches and lifts away elsewhere. A clean positive line and an open counter need different amounts of space:

• Fine lines hold. A positive line down to 0.1 mm can stamp; designing to 0.15 mm or more gives the crispest strike.
• Give gaps their own measure. Heat and pressure reach beyond the die edge. Use 0.25 mm as the design target; only gaps below 0.15 mm need a local opening.
• Let the sheet speak. Texture changes how an edge catches light. Our team checks the actual artwork and stock together without simplifying the customer’s mark.

The type rows follow the same physics. 7 pt minimum for positive foil type, 8 pt recommended, in a low-contrast face. 10 pt minimum, medium or bold weight, for type reversed out of solid foil, because the paper-colored letters are gaps, and gaps fill in. 12 pt minimum for high-contrast serifs such as Didones, whose hairlines are far thinner than the stems. Foil registers to print within ±0.5 mm and to a second foil within ±0.25 mm. And QR codes and barcodes are never foil; the modules bridge and the code stops scanning. More in foil artwork preparation.

Raised foil and raised spot UV: target and floor

Raised foil and raised spot UV use 0.3 mm (0.85 pt, 0.012 in) line and gap targets, with a 0.17 mm floor. Positive type stays at 8 pt and reversed type at 10 pt. The coating flows before it cures; these targets keep the bead defined and the spaces open.

Letterpress: fine lines hold, reversed lines close

Letterpress holds positive lines down to 0.1 mm (0.28 pt), with a 0.15 mm (0.43 pt) design target. Internal gaps target 0.25 mm, floor 0.15 mm; reversed lines stay at 0.3 mm. Type remains 7 pt positive and 10 pt medium or bold reversed.

The photopolymer plate holds fine relief well, which is why letterpress suits delicate linework. What limits it is ink gain. The inked plate is pressed hard into the sheet, and the pressure squeezes a little ink outward from every printing edge. A positive stroke gains on both sides and gets slightly heavier, which it can afford. A reversed line or a counter loses on both sides and closes up, more so on soft cotton, where the impression pulls the ink along with the fibers.

Two more limits come with the ink. Keep solid areas under 13 cm² (2 in²) on cotton; a big flood bottoms out the plate and mottles. And letterpress ink is translucent, so light ink on dark stock isn't offered; use foil. Colors register within ±0.3 mm, with a 0.3 mm trap where they touch. Setup is in letterpress file setup.

Emboss and deboss: the paper has to bend

Emboss and deboss need strokes of at least 0.5 mm (1.5 pt), 1 mm between raised or recessed elements, and type at 10 pt minimum in a medium or bold weight, with no hairlines.

There's no ink here. The image is paper pushed up or pressed down between two metal dies, and you read it by the shadow along its edges, so the minimums are about how tightly paper fibers can bend. A stroke thinner than 0.5 mm becomes a crease, not a shape. Two forms closer than 1 mm merge, because the paper between them can't come back down in that distance. Small or light type has too little edge to cast a shadow, which is why blind type under 10 pt disappears on cotton.

Stock matters as much as art: uncoated or cotton, 16 pt (0.4 mm) or heavier, and 32 pt for a deboss that must not show through on the back. Emboss won't seat cleanly on soft-touch or silk laminate. Depth runs 0.3–1.0 mm. Details in emboss and deboss file setup.

Flat spot UV: 0.3 mm lines, 0.5 mm gaps

Flat spot UV holds a 0.3 mm line, needs a 0.5 mm gap and 8 pt type. The coating is a liquid laid on the sheet and cured under UV light; before it cures it flows a little, which rounds fine lines and closes narrow gaps. It registers to print within ±0.5 mm, so don't draw a UV outline that depends on a tighter fit: a gloss keyline 0.3 mm around a printed logo will visibly miss on one side. Spot UV soaks into uncoated and cotton stock, so it runs on coated or laminated stock only. See the spot UV guide.

CMYK: the finest line, with two catches

Four-color printing holds a 0.1 mm (0.25 pt) positive line and 6 pt type. Reversed, it needs 0.2 mm (0.5 pt) lines and 8 pt type, or 9 pt on uncoated stock.

• Catch one: misregistration. Cyan, magenta, yellow and black are four separate impressions, and they never land in exactly the same place. The matrix puts that at ±0.15–0.25 mm. A fine line or small letter built from four inks shows colored fringes when they drift. Build fine lines and small type in one ink, usually K100, and keep rich black (C60 M40 Y40 K100) for areas at least 5 mm across.
• Catch two: dot gain. Ink spreads as it hits paper, more on uncoated stock than coated. Reversed type out of a dark four-color background gets filled in from four directions at once. That's why reversed type needs 8 pt, and 9 pt on uncoated.

Keep total ink at 300% or less and the lightest tint at 8%. On dark dyed-through stock CMYK simply disappears; use foil or white ink. More in CMYK, rich black and ink limits.

Die cutting and laser cutting: the minimums are distances

A cut line has no printed weight; it's always a 0.25 pt stroke in the CUT swatch. What limits a cut is geometry: 1.3 mm (0.05 in) minimum inside corner radius, 3 mm between two cuts or between a cut and the trim, and a tolerance of ±0.8 mm across a stack.

A steel-rule die is a blade bent to your shape, and a blade only bends so tight, which is where the 1.3 mm inside corner comes from. Two cuts closer than 3 mm leave a strip of stock too narrow to survive, and it tears. Laser cutting is finer: 1.0 mm gaps between cuts, 1.0 mm bridges, 0.8 mm slots, a 3 mm frame to the card edge, and ±0.5 mm between plies. Any closed cutout, like the counter of an O, needs bridges or the center falls out. Setup is in die cut file setup and the laser cut file setup guide.

Positive vs reversed: why reversed always needs more

Every process spreads. Ink squeezes outward, foil bridges, coatings flow, paper fibers pull. Spread makes a positive stroke a little thicker and a reversed stroke a little thinner, so reversed lines and reversed type always need a larger minimum than positive ones.

How type size relates to stroke thickness

Point size measures the type body, not the stroke. The same 7 pt can mean a 0.15 mm stem or a 0.37 mm stem, depending on the weight.

Type has its own rows in the matrix. Point size does not tell you the width of a hairline or counter. Keep the existing 7 pt positive / 8 pt recommended foil type guidance, and measure strokes and gaps separately against their floors.

Measure the weakest stroke: a hairline serif, crossbar or taper. A light face is not automatically unsuitable for foil. Preserve the chosen lettering and check it at its printed size, including x-height and counters.

How to measure line weight in Illustrator and InDesignHOW TO CHECK

Measure every line and gap at the size it prints, in millimeters. Never judge it by eye on screen.

1. Set units to millimeters. Illustrator: Preferences > Units. InDesign: Preferences > Units & Increments.
2. Work at final size. A logo placed at 40% in InDesign prints its strokes at 40% too, so measure the artwork at the size it will print, not the size it was drawn.
3. Live strokes: select the path and read the weight in the Stroke panel. Check Scale Strokes & Effects: with it on, a 1 pt stroke on a logo scaled to 30% becomes 0.3 pt.
4. Outlined shapes have no stroke weight to read. Use the Measure tool (grouped with the Eyedropper in both apps; the distance shows in the Info panel) across the narrowest point, zoomed to 800% or more, snapping to anchor points.
5. Measure the gaps too: every counter, the space inside and between letters, between two lines, and between a line and a foil flood.
6. Try the coin test on a copy: a 0.15 mm circle gauges the positive-line target and a 0.25 mm circle gauges the gap target. Missing a target is not a failure: measure against the 0.1 mm line and 0.15 mm gap floors before changing anything.
7. View at 100% (actual size) to judge how the detail reads, then go back to the numbers.
8. Outline strokes on finish layers before export (Object > Path > Outline Stroke) so no stroke setting can change on the way out. Leave CUT and CREASE lines as strokes.

Common fails

• Script fonts. Measure entry strokes and joins at final size against the 0.1 mm floor; 0.15 mm is the target. Preserve the lettering’s character.
• Didone hairlines. Keep the 12 pt foil type minimum and measure the finest strokes, not only the main stems.
• Thin-stroke icons. Screen pixels do not establish printed width. Measure at final size and adjust only below-floor detail, never redraw the whole mark heavier.
• Tiny taglines under logos. The logo gets scaled to fit the card and the tagline beneath it drops to 4 or 5 pt. Check the tagline on its own; set it separately at the minimum, or leave it off.
• QR codes in foil. Never. The modules bridge, the quiet zone fills, and the code stops scanning. QR codes and barcodes are always ink.
• Hairline keylines and borders. Measure the exported outline: foil targets 0.43 pt (0.15 mm), with a 0.28 pt (0.1 mm) floor. Emboss and UV keep their separate limits.
• Foil art reused for emboss. A combination die follows the stricter emboss geometry: 0.5 mm strokes, 1 mm gaps and 10 pt type. Foil alone can retain finer detail.

Before you send

• Foil positive lines: 0.15 mm target, 0.1 mm floor
• Foil gaps and counters: 0.25 mm target, 0.15 mm floor
• Foil type is 7 pt or more positive (8 pt recommended), 10 pt medium or bold reversed, 12 pt for high-contrast serifs
• Letterpress positive lines 0.15 mm target / 0.1 mm floor; internal gaps 0.25 mm target / 0.15 mm floor; reversed lines 0.3 mm; type 7 pt / 10 pt reversed
• Emboss strokes 0.5 mm, gaps 1 mm, type 10 pt medium or bold
• Flat spot UV lines 0.3 mm, gaps 0.5 mm, type 8 pt
• CMYK lines 0.1 mm, reversed 0.2 mm; type 6 pt, reversed 8 pt (9 pt uncoated)
• Die cut inside corners 1.3 mm radius or more; cuts 3 mm apart and from trim
• Measured at final size, with strokes outlined on finish layers
• No QR codes or barcodes in foil