Packaging Print and Color: Prepress Checks That Work

Define the printing condition before anyone picks a color

A color reference means little until you name the press, the substrate and the ink set that will carry it. Prepress exists to prepare a job for a real world printing condition, and every later decision about ink, proof and tolerance hangs off that definition. Write it on the job sheet: substrate grade and finish, process ink set, whether the press is conventional or extended color gamut, and which spot inks are named.

If that line is blank, the pressroom inherits the ambiguity. A warm red approved on coated white board may reproduce differently on uncoated kraft; file edits alone cannot establish a match. Ask the printer to state the printing condition in writing and explain which proof type represents it.

• Substrate brand, grade and finish.
• Process ink set and whether extended gamut is in use.
• Named spot inks, listed once and spelled consistently.
• The proof type that represents the condition.

Keep brand spot colors as named inks

On plated presses, a dedicated spot ink generally uses its own plate. A named spot color may instead be emulated from a digital or extended-gamut press ink set, so confirm the intended workflow. A process build can shift as its component inks vary, but the brand reference can still be retained as an approval target. A dedicated ink may offer a separate adjustment route; measurement and control methods depend on the press and printer.

Extended gamut presses can emulate many spot colors from a fixed ink set. Adobe states that for spot colors defined with spectral values, its PDF Print Engine can extract CxF data for conversion and ICC-based color management. That is a real capability, but emulation is a match decision, not an automatic equivalence. Ask for a drawdown or a proof on the actual substrate before you retire a named ink.

• Name each spot ink identically across artwork, dieline and purchase order.
• Confirm whether the chosen press will print the spot as a plate or emulate it.
• Ask the printer to state the tolerance they will hold, in writing.

Preflight separations and color warnings

Output preview in Acrobat lets you view separations, toggle process and spot plates, and inspect color warnings, including unintended rich black on type. Use the appropriate simulation profile when assessing output. Filtering by source color space helps locate RGB objects for review, but RGB is not inherently an error: managed RGB may be acceptable in PDF/X-4 and other workflows if the printer supports it.

Treat separation preview as one inspection tool, not complete production approval. Adobe documents that this preview does not show trapping, emulsion options, printer marks, or halftone screens and resolution, and recommends checking those settings with the print provider using integral or overlay proofs. Agree with the printer which proof or production check is appropriate for the actual workflow.

• Check that the spot plate list matches the ink list on the job sheet.
• Look for four color builds on small text and thin rules.
• Ask the printer for the total area coverage limit rather than guessing one.

Marks, boxes and bleed

Printer marks can help a provider align separations, calibrate ink density and trim sheets. Ask which marks the printer wants supplied rather than adding them automatically. TrimBox describes the intended finished page boundary, BleedBox describes the bleed extent, and ArtBox describes meaningful artwork bounds, not a cutting path. For shaped packaging, check the approved dieline separately. Set the required page boxes in the source file and verify them after export.

Adobe notes that marks added later in Acrobat can overlay marks already exported from InDesign and may not align perfectly, so decide once where marks are generated. Expanding a crop or media box later changes what the preview shows, which is why box edits deserve a second look before release.

• Where backgrounds or images reach a cut edge, extend them beyond that edge by the bleed amount specified by the printer or converter.
• Confirm with your printer where marks should sit and whether they want marks and dieline on separate layers or supplied separately.
• Dieline revision appears in the file name, not only on the artwork.

A hypothetical label to show the arithmetic

Suppose a label face measures 90 mm by 120 mm, which is 10,800 square millimetres or 108 square centimetres. A brand color panel covers 35 percent of that face. The spot ink area per label is 108 multiplied by 0.35, which equals 37.8 square centimetres.

For a hypothetical run of 20,000 labels, total spot ink area is 37.8 multiplied by 20,000, which equals 756,000 square centimetres, or 75.6 square metres. If the same panel were rebuilt from three process inks and, as a simplifying assumption, each ink covered the full panel, the combined ink area would be 75.6 multiplied by 3, which equals 226.8 square metres. Real builds use varying tint percentages, so actual coverage per ink would differ.

This hypothetical calculation sums covered area across ink separations; it does not predict ink volume, waste, production cost or color match. Those depend on factors beyond panel geometry, including tint values and the printing process. Ask the printer to compare the proposed workflows and explain how the chosen proofing method will assess the brand-color target.

Decision table: which check answers which question

Use the table to assign checks and approvals explicitly. Confirm production trapping with the printer, and identify who has authority to approve brand color. A file proof can show intended geometry, but it does not establish actual cutting accuracy.

Release checklist

Work through this list before the file leaves your desk. It is Teal's editorial planning framework for organizing the handoff, not a standard or a certification.

• Printing condition, substrate and ink set written on the job sheet.
• Every spot ink named the same way in artwork, dieline and purchase order.
• PDF exported from the source application rather than converted from a general purpose file where that can be avoided.
• Output preview checked for separations, color warnings and RGB handling against the printer's requirements.
• Required page boxes verified, with artwork and bleed checked against the approved dieline.
• Printer-requested marks generated without duplication, or omitted if the printer will add them.
• Barcode and legal copy checked at final size on a proof, with barcode verification arranged separately where your channel or printer requires it.
• Agreed proof approved for its stated purpose, with any differences from the production substrate understood and additional substrate checks arranged where needed.
• Trapping and screen rulings confirmed with the printer, not assumed from the preview.
• Revision number on the file matches the approved proof.

Scope and limits

This guide covers prepress decisions for printed packaging. It does not set color tolerances, ink limits or screen rulings for your job, and it does not determine regulatory labeling content. Those come from your printer, your converter and the rules that apply to your product and market.

Channel specific artwork or barcode requirements imposed by a retailer or marketplace must be confirmed in your own agreement with that channel. Nothing here should be read as a statement of what a retailer currently requires.

The checklist above is Teal's editorial planning framework. The cited Adobe sources support specific technical points about rendering, preview and page marks, not the whole workflow.

Where to go next

Once the printing condition and ink list are settled, proofing and dieline checks remain important parts of the handoff. Agree the proofing method early; consider a production-substrate proof or ink drawdown where substrate effects matter. Keep the approved reference, its viewing conditions and the released file together for future comparisons.

Questions about Packaging print and color prepress