Spot colors & print separations

A spot color is a named ink the printer runs on its own plate — a separation — instead of building the color from CMYK on press. You reach for spot inks for two reasons: exact brand colors that must hit the same value on every job, and finishing processes like die cutting, varnish and foil that aren't "colors" at all but instructions to the machine. Popcorn Editor treats both the same way: give the ink a name, and it exports as a matching separation.

Create a spot color#

Spot inks live in the Swatches panel in the Properties panel on the right. Click New swatch, then set Type to Spot.

The Name is the contract. It's the exact string your print service expects to see on the separation — for example die cut or Foil Gold — so it's validated as you type:

• It can't be empty.
• It can't contain #.
• It must be printable ASCII, up to 100 characters.
• All and None are reserved separation names and can't be used.

Names are also case-sensitive to the printer. If you create both Die Cut and die cut, Popcorn Editor warns that they differ only by case — those become two separate plates, which is almost never what you want. It also flags a name that matches a process ink (like Cyan), because that spot may merge into the process plate at the RIP.

Spot names are user data and are never translated or auto-corrected. Type them exactly as your print service specifies them.

Purposes: presets for finishing#

Most spot inks aren't bespoke — they're standard finishing plates every printer recognizes. The Purpose dropdown pre-fills the name, preview ink and overprint setting for the common ones so you don't have to remember the conventions:

There's also Custom for anything else. As the in-app hint says, presets fill in the name and preview ink print services expect — the name stays fully editable, so you can always tweak it to match a specific vendor's requirements.

Preview ink is soft-proof only#

The Preview ink (CMYK) value controls only what the spot looks like on your screen. It has no effect on the separation that's emitted at export — that's driven by the ink's name, not its preview. Pick a preview color that's easy to see and roughly stands in for the finish (a magenta for a die line, a pale tint for varnish); it's a working proxy, not a color you're asking the press to reproduce.

For brand inks where the on-screen proof actually matters, expand Measured Lab color. A measured CIELAB value gives a more accurate on-screen proof and exports a /Lab separation alternate, while the CMYK preview stays as the fallback bridge. Use it when you have a real measurement; skip it for pure finishing plates.

Overprint vs knockout#

By default, artwork knocks out whatever is behind it — the top object punches a hole through the layers below so inks don't mix. That's wrong for most technical spots. A die line, a varnish flood or a white underbase should sit on top of the artwork without removing it.

The Overprint toggle handles this. As the hint puts it, technical inks (die lines, varnish, white) usually overprint so the artwork beneath prints intact. When overprint is on, the swatch row shows an OP badge so you can see at a glance which inks are set to overprint. The finishing presets turn it on for you where it's expected.

A die cut line that isn't set to overprint will knock a white gap out of your design where the line runs. If you see an unexpected outline in your proof, check the spot's overprint setting first.

Tint and detach on applied objects#

Once a spot is applied to an object, its color field in Properties reads Spot color and exposes two controls:

• Tint (0–100%) — prints a screened percentage of the ink. A 40% tint of a foil or brand spot uses the same plate at a lighter strength, with no extra separation.
• Detach — breaks the link to the swatch and converts the object back to a regular process color, keeping its current appearance. Popcorn Editor confirms this because it's a one-way conversion off the named plate.

Separations export from CMYK only#

This is the rule that trips people up most: spot colors only export as separations from CMYK documents. In an RGB document there are no ink plates to attach a spot to, so there's nothing to separate.

If you try to use a spot in an RGB document, Popcorn Editor shows an amber warning — "This document is in RGB mode. Spot colors only export as separations from CMYK documents." — with a Switch to CMYK link right there to fix it in one click. Set your document to CMYK early, and this never comes up. See RGB & CMYK color modes for how to switch.

Notes to the printer#

Finishing plates often carry requirements that aren't visible in the artwork — a stroke weight, a fill rule, a minimum area. The Note field on the swatch records them (for example "1pt stroke, no fill"), so the instruction travels with the file instead of living in an email your print service will lose.

What preflight catches#

The print checks run before export and flag the spot-color mistakes that cost a reprint. Watch for:

• Spot used in an RGB document — switch to CMYK to export separations.
• Names differing only by case — these become separate plates at the printer.
• A spot matching a process ink name — it may merge with that process plate.
• Spot objects with effects, masks or gradients — these rasterize to process CMYK and lose the separation; a background-blur effect can rasterize the whole canvas.
• Text in a spot color — it always exports as vector outlines, never selectable text.

Formats that can't hold spot data flatten your inks to their preview values, so preflight names exactly which spots would be lost. Fix issues here rather than discover them on the proof.

Next#

Turn this into a finished file with Exporting a print-ready PDF, and see the whole workflow end to end in Design your own product labels.