Spot UV Coating Explained: Gloss Where It Counts

Spot UV coating puts a clear varnish on parts of a printed sheet and cures it under UV light. Those parts come out glossy, and everything around them stays as it was.

It usually happens last, after the ink is dry. You’ll see it most on business cards, book covers and folding cartons, laid over matte or soft-touch lamination.

On digital coaters, thickness is a file setting and not a separate process. Duplo’s DuSense coaters read the grayscale value of each shape in the spot file, and on the DDC-8000 that sets a polymer layer anywhere from 10 to 80 microns (Duplo USA, 2025).

Darker black means thicker varnish. One file gives you flat gloss and raised relief both.

What Is Spot UV Coating?

Contrast is the whole point. A glossy logo on a matte card catches the light and reads like it sits on its own layer.

The varnish goes down in a separate pass once the ink has dried, so the artwork stays visible underneath. A thin film feels flat. A thick one you can feel with a fingertip.

It’s a finishing step, not a printing method.

You’ll see it sold as spot varnish, spot gloss, selective UV, 3D spot UV or raised UV. xTool lists the first three as one process and treats raised spot UV (also called 3D spot UV or raised UV) as the thick-film variant.

People mix it up with a few neighbors. UV printing dries the ink itself under UV light, while spot UV varnishes a sheet that is already printed, as Colour Graphics explains in its spot UV guide.

Flood coating comes down to coverage. How spot varnish and flood varnish differ is simple enough: flood covers the entire sheet for an even shine, and spot covers only the elements you pick.

Inline UV coating is the one that trips people up. Qin Printing separates the thin coat applied during the press pass on a UV offset press from offline spot UV, which builds a thicker, more dramatic effect. The inline version costs less because it adds no production step.

What Spot UV Coating Is Made Of and How It Cures

Under the lamp, a liquid turns into a solid film. The mix is mostly acrylate oligomers and monomers, plus photoinitiators that absorb the light and release free radicals. Those radicals link everything else into a crosslinked film.

Cure is nearly instant. Friesens describes the varnish hardening as soon as it meets UV light, and PCI Magazine’s RadTech news notes the liquid becomes a solid finish without significant loss of thickness or weight.

Nothing evaporates, so a thick layer stays thick. That’s what makes raised effects workable.

The oligomers are the backbone of the film. A coating patent (US 10,577,516) lists viscosity, durability, flexibility, adhesion and wetting among the properties they control. Monomers thin the mix so it can be screened, rolled or jetted, then join the network during cure.

Which photoinitiator works depends on the energy source, the resins used and the cure speed you want, according to the same patent. Some formulas also add wetting agents that help the varnish flow and level.

Digital coaters use the same chemistry in jettable form. Scodix presses fire a clear polymer cured by UV-LED, and MGI describes the coating on its JETvarnish 3DS as solvent-free.

Mercury Arc Versus UV LED Curing

Baldwin Technology, a UV curing equipment maker, says mercury arc lamps give off broad-spectrum UV and a lot of heat, while LEDs emit only UVA and run cool.

Low heat protects heat-sensitive stock and laminate film.

Photoinitiator choice depends on the lamp, so a varnish built for mercury output won’t automatically cure under LED. Coater and varnish have to be matched.

Spot UV Application Methods and the Thickness Each Produces

Thickness ceiling and setup cost both depend on how the varnish goes on. Screens and plates, inline or offline coating units, and digital inkjet coaters all get used for spot UV, and the published numbers differ a lot between them.

• Friesens’ screen or plate machines lay down 10 microns as standard and 100 microns at most per pass
• Raised spot UV on 4OVER4 cards runs 50 microns (4OVER4, 2025)
• The Duplo DuSense DDC-8000 covers 10 to 80 microns (Duplo, February 2025)
• MGI’s JETvarnish 3D goes from 3 to 200 microns with the Twin print engine (MGI product literature)
• Scodix Ultra reaches 5 to 250 microns in one pass (PrintWeek review of the Ultra 6000)

Screen and Inline Application

Screen printing is the traditional route. A dedicated screen carries the varnish pattern, so every job needs its own, according to xTool.

JingSourcing’s overview splits the work by method. Roll coating handles full-surface flood coats, and screens handle spot, raised and textured effects. On a UV offset press, the coating cures in the same pass as the CMYK inks, per Qin Printing.

Sources disagree on what screens can do. xTool, a desktop UV printer maker, calls raised spot UV a digital-only capability because screens cannot build thickness in controlled passes.

Friesens, a book manufacturer, applies varnish with a screen or plate and names 100 microns as the most its UV machines lay down in one pass.

Both can be right. One statement is about layering in controlled passes, the other about what a single pass deposits.

Digital Spot UV Coaters

On Duplo’s DuSense, thickness comes from grayscale values in the spot layer file, and the operator fine-tunes a threshold on the controller. As of Duplo’s February 2025 guide, thin coats need its DUV-410 varnish.

Scodix Ultra Pro carries separate polymers. Spot 80 is the low-build one, engineered to mimic litho or screen-printed spot UV, and PolySense 100 is the hi-build version for raised work, per PrintWeek.

MGI’s JETvarnish 3D needs no plates or screens and skips costly makeready. It varies thickness inside a single design through file management, which creates texture.

No screen means no screen cost, so short runs stop being a penalty. MGI’s launch literature says spot UV and 3D effects carry no minimum quantity.

Raised and Textured Spot UV

Raised spot UV is the same process with a thicker layer. It works as an accent, not a flood, and 4OVER4 keeps the coated area under about 30 percent of the design for the cleanest results.

Thick varnish also spreads slightly, so Made Good Designs advises more generous spacing and minimum sizes than flat gloss needs.

Which Paper Stocks and Base Finishes Work With Spot UV Coating?

Coated stock with a matte or soft-touch laminate gives the best result. Spot UV works through contrast, so a flat base makes the gloss visible and a shiny base hides it.

Matte and soft-touch laminate are the good bases. Gloss coated stock is a poor one because the accent nearly disappears, and uncoated stock is worse in its own way, since the varnish soaks in.

OVER4’s production team says varnish over a gloss stock blends into the sheet and leaves almost no visible effect. Made Good Designs treats matte laminate plus spot UV as the benchmark pairing for a premium look.

Soft touch goes a step further. Its velvety, suede-like surface makes the gloss look more dramatic, which is why 4OVER4 calls it the most popular pairing. Heavier cardstock also holds raised varnish more cleanly.

Laminate and spot UV do different jobs. Lamination is a film that protects the sheet and sets the base finish, while the spot UV on top is a liquid that cures into a thin glossy layer (see how varnish and lamination compare in print).

Sources split on color. Made Good Designs says the varnish catches light without changing colors, while PakFactory says gloss over soft matte laminate makes the colors beneath look darker.

Ask for a physical sample before approving.

Uncoated stock is where the advice divides. 4OVER4 says spot UV, including the raised version, cannot go on uncoated or cotton paper because the fibers absorb the coating.

The split comes from how coated and uncoated paper stock handle a liquid varnish. A coated sheet seals the surface. An uncoated one soaks the varnish in and kills the contrast.

Digital systems claim a way around it. Scodix markets multi-layer embellishment on its Ultra 2500 series for uncoated substrates and points buyers to a recommended substrate list. Its Ultra presses also offer polymers tuned to different surfaces, avoiding corona treatment, pre-coating or lamination (PrintWeek).

MGI says its JETvarnish 3D coats digital prints directly, with no lamination required.

Still, treat uncoated spot UV as a printer-specific service and not a standard option.

Folding cartons typically run on solid bleached sulfate (SBS) board, a white virgin-fiber paperboard. Clearwater Paper’s Candesce SBS range is sold in a C1S (coated one side) folding carton version, which gives the varnish a coated print side to sit on.

How to Set Up Artwork for Spot UV Coating

The printer needs two files. One is the print artwork with no varnish in it, and the other is a spot file holding only the shapes to be coated, filled solid. The press runs the first, then the coater reads the second.

1. Finish and approve the base artwork. The spot shapes are copied from it, and Worldwide advises approving the design before building the varnish area.
2. Duplicate the elements that should gloss onto a new layer.
3. Fill them solid. Tints and gradients are not accepted, according to Athlone Printing.
4. Convert text to outlines and keep every shape as a vector.
5. Apply the fill your printer specifies (the options are below).
6. Export two PDFs: the print file with the spot layer hidden, and the spot file with only the spot layer visible.
7. Open the combined file in Acrobat’s Output Preview and confirm the spot swatch shows and overprint is applied.

Raster shapes print with soft or uneven edges. Topac says vector shapes give a much sharper edge, and the difference between vector and raster artwork for print shows why.

Printers do not agree on the fill. Tradeprint, Walsworth and PrintNinja ask for solid black shapes on a white page, where black marks the varnish. Worldwide and CBS Printing want a swatch named Spot UV instead, and Athlone wants one called SPOT-UV with its color type set to Spot.

Neither convention is wrong. A file built for one printer fails at another, which is why Tradeprint warns that a change of printer often means a different setup.

Overprint keeps the varnish shapes from knocking out the artwork beneath them. If white holes show in the preview, check overprint versus knockout settings first.

Registration tolerances vary too. Tradeprint quotes about plus or minus 0.5 mm for its process, while Athlone, which applies varnish by screen printing, allows plus or minus 2 mm. Athlone’s workaround is to overlap a hard printed edge with the spot shape by 2 mm, so a shift leaves no gap.

Worldwide sets a minimum line weight of 0.5 pt, and 4OVER4 recommends at least 1 pt for spot gloss and foil. Use the printer’s own figure, not a general rule.

Setup in Adobe Illustrator

Newprint’s layer method keeps CMYK or Pantone elements on one layer and the spot UV objects on a layer named Spot UV, then saves two PDFs.

Tradeprint works with artboards instead. It builds four, with front and back artwork on top and the spot UV front and back below, the shapes in 100% black.

If only one side gets varnish, the other spot artboard stays in the file, blank. Outline the text before saving to avoid font substitution.

Setup in Adobe InDesign

Worldwide’s guide builds the named swatch first, then exports three PDFs from one layered file.

• Guide, with every layer visible
• Print, with the spot layer hidden
• Spot UV, with the CMYK layer hidden

The guide file is only a reference. Only the print and spot files go to the press.

Tradeprint’s page method mirrors its artboard one, with pages 1 and 2 carrying the artwork and pages 3 and 4 the spot UV. Instantprint also asks for a preview file that shows the varnish layered over the artwork.

Spot UV Coating Compared With Flood UV, Aqueous Coating, Foil Stamping and Embossing

Pick by the effect you want. Contrast inside a design points to spot UV, an even shine across the sheet to flood UV, metallic color to foil, and physical relief to embossing.

Flood coating protects and shines but doesn’t accent anything. Go with spot when the design needs a gloss highlight, and flood when the whole surface should shine.

Aqueous is a different story. Kennesaw State’s print shop FAQ says it dries with hot air while UV cures almost instantly, and that UV is tougher, more slippery and glossier. A ballpoint pen writes on aqueous but not on most UV.

Signs.com adds that aqueous is almost always flooded, because spot-coating it is harder than with UV, and that it generally costs less. For a selective gloss effect, UV is the practical route.

Made Good Designs calls spot UV clear and refined and foil opaque and bold. Foil also needs a custom metal die, and each foil color needs its own die and stamping pass, according to Qin Printing.

On uncoated paper, clear gloss foil is the closest substitute. After Hours Creative Studio says the finish is near-identical to spot UV, except it is pressed into the paper instead of raised, and this overview of foil stamping in design covers the process.

Embossing presses relief into the stock with a die, so it reshapes the paper instead of adding a layer. Made Good Designs notes short runs feel the tooling charge most, and sculpted dies cost more.

Combining the two raises a registration question. Friesens reviews any design that pairs spot gloss UV with embossing before approving it.

Made Good Designs recommends one lead finish and one supporting finish per piece, with spot UV in the supporting role.

What Drives the Cost of Spot UV Coating

According to 4OVER4, spot UV adds a modest premium over a standard matte or gloss finish rather than doubling the price. Most of the premium is tooling. Traditional spot UV needs a separate plate or screen per design, which 4OVER4 gives as the reason it costs a bit more than full UV coating.

Run length matters because quantity spreads the setup cost across more pieces. Neopost’s Jimmy Nguyen said traditional spot UV needs a certain run length to justify its make-ready costs.

Coated area counts too. Gelato’s Connect documentation prices spot UV as a material cost per unit of area, plus make-ready labor per section. Thicker layers put down more polymer, and Scodix said its low-build polymer costs the printer less for that reason.

Spot On Finishing, a Sydney trade finisher, launched around a Duplo UV Coater so print shops could order short-run spot UV without traditional make-ready.

Foil is the comparison people reach for first. Made Good Designs says the per-unit gap with foil narrows on larger runs, since the die cost spreads thinner.

Flat spot UV over a matte base is the cheap premium finish. Made Good Designs rates it the best return when the budget cannot carry foil or embossing tooling.

Raised and pearlescent variants cost more, according to JingSourcing. Pay for height only when the piece will be handled.

When Spot UV Coating Fails

Folds crack it, fine detail fills in or vanishes, registration drifts, adhesion gives out on some surfaces, and recycling gets awkward. Each one has a cause worth knowing before you send files.

Cracking on Folds and Scores

A hard coating bent along a fold cracks. 4OVER4 calls it a normal reaction, not a printing defect.

It gets worse with UV and other hard coatings (compared with matte or uncoated finishes), with heavier cardstock, with dark heavy ink along the fold, and with a shallow or missing score.

Duplo’s February 2025 setup guide tells designers to keep spot coating off cut and fold lines. On a packaging file, the dieline marks every fold and cut, so lay the spot layer over it before export.

OVER4 recommends scoring before folding and keeping heavy ink and coating off the exact fold line where possible. Ironmark notes aqueous coating is more flexible than hard UV, which cracks when creased.

Fine Detail and Registration Drift

Fine lines can fail from either direction. Varnish bridges small gaps, and 4OVER4 says very fine detail can fill in or drop out. Going the other way, Friesens notes that a very fine line carries too little varnish to show gloss against the matte around it.

Registration drift starts in the files. CBS Printing requires the spot PDF to match the original artwork in every respect, size included, because any difference shifts every edge.

Athlone also keeps spot elements at least 3 mm from the trimmed edge.

Adhesion Failures

Topac’s silk-screen spot varnish specification states that its varnish has no adhesion over gold, silver, bronze and other metallic tones unless a laminate coating has been applied first. It also says UV offset varnish cannot be overprinted with silk-screen spot varnish, and that laminate should be applied there too.

At printers that work this way, lamination is a requirement on those surfaces, not only a contrast choice.

Recyclability of Cured Varnish

Sources disagree on whether UV-cured layers recycle cleanly.

RadTech reports that in version 2 of the 4evergreen Circularity Guidance, UV/EB inks were marked fully compatible with the standard recycling process in almost every category.

Siegwerk is more cautious. Testing to INGEDE Method 11 with Stora Enso since 2017, it found standard UV and LED UV inks leave visible dirt specks in recycled paper because the cured film resists breaking up. Its newer deinkable UV flexo varnishes do recycle in standard flotation deinking.

Neither source tests screen-printed spot varnish directly, since both cover inks or flexo varnishes. Ask the printer whether its varnish system has passed INGEDE Method 11 testing.

Spot UV Coating FAQ

What is blind spot UV?

The varnish goes on unprinted areas, so the design shows only as a subtle sheen. Regular spot UV does the opposite and glosses printed elements such as a logo, according to eufyMake.

Which spot UV finishes exist besides gloss?

Printers also offer matte, pearlescent and sand versions. Matte is a subtler, non-reflective coat (SAPC), pearlescent blends gloss UV with metallic flecks (CustomBoxMakers), and sand UV leaves a semi-matte, raised grain (Qin Printing).

Is spot UV scratch resistant?

Yes. Made Good Designs says cured UV varnish holds up to handling and resists scratches.

The weak spot is the fold, where the hard film can crack.

Can spot UV go on both sides of a sheet?

Yes, if the product is set up for it. Athlone applies spot UV to front pages only unless the product is double-sided.

Tradeprint’s files carry a separate spot layer for each side.

Can a desktop UV printer do spot UV?

Yes. Desktop UV printers from makers such as eufyMake print the color design first, then jet clear varnish from a black-and-white mask file.

The two files must line up exactly, so run a test sheet before a full batch.

What to Confirm With the Printer Before Approval

Check the base finish and stock first, then the fill convention and registration tolerance, then a physical sample with the fold placed where it will really fall. The order matters.

Stock goes first because it decides whether the gloss shows at all. The file convention comes second because specs differ from shop to shop. The sample goes last because only a finished piece tests base, registration and fold together.

The trade-off is a proofing step before the run. In exchange, a mismatched fill or a cracked fold shows up on one sheet instead of the whole batch.

As of October 2026, printers publish their own fill conventions and tolerances, with no shared standard in the specifications checked. A published standard would replace the printer-by-printer check.

Once the spec is confirmed, the base layer still needs setting up as a print-ready file.

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Bogdan Sandu

Bogdan Sandu is a seasoned designer who has been designing websites since 2008.

Renowned for his expertise in logo design and visual branding, Bogdan has developed a multitude of logos for various clients.

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