Contract colour: digital mock-up versus Heidelberg production sheet

A mock-up is not a press sheet

A screen JPEG, a PDF on a laptop, and a 3D gift-box render are sales tools. They are not a Heidelberg production sheet. Lighting, RGB, and holographic film will move. Write which proof is contractual: digital, wet proof, or press sheet.

We print wrap and carton sheets in the same Longgang plant after Kodak CTP. Colour you can hold is ink on paper from that path — not a filtered mock-up of gold foil.

If the buyer signs only a screen PDF, say so on the RFQ. We will still print a sheet; we will not treat the PDF as the keep-sheet unless you name it as the contract proof — and we will warn that it will not match foil or holographic wrap.

• State which proof is contractual.
• Spot foil and UV sit outside a CMYK proof.
• Approve wrap sides, not only a front hero.

What we can match

A printed wrap sheet or carton from the same press family is a matchable object. Pantone on coated paper is a start. Uncoated kraft, coloured board, and holographic film will shift; say if that shift is acceptable.

If the brand has a viewing-booth standard, send it. Otherwise we OK on a daylight sheet. Returning last year’s physical wrap is better than a hex code in an email.

What we will not promise in an article

We will not invent Delta-E numbers, a fake spectro log, or a guaranteed match to a phone photo. Those claims belong in a QC protocol you attach — not in marketing copy.

Catalog photos of pink, kraft, or holographic boxes are colour/structure references. They are not a locked ink formula you can reorder by nickname.

Spot versus process

Brand red on a book-style box is often a spot. Process-only CMYK will drift lot to lot, especially on large solids. Write spot versus process on the RFQ, and which panels carry the brand colour.

Heidelberg catalog names (8-open 4/5, XL-75 4/5, CDX102 4/5/6) describe in-house sheetfed capacity. They do not mean every job is six-colour. Extra units are for when the map needs them.

Foil, UV, and film live beside ink

Foil, spot UV, and lamination sit on a finish map. A CMYK digital proof will not show foil bounce or UV gloss. Approve those on a physical dummy or a drawn map plus a sheet, not on the mock-up alone.

Holographic wrap will not match a social-media render. Say if movement is acceptable. Do not treat a GIF of sparkle as a contract.

Who signs which face

Approve all wrap sides that print, including spine, lid inner if printed, and dust flaps if they show. A hero front OK does not cover a mismatch on the base.

Structure sample and colour sample can be two rounds. Fit of a lid is not colour. Do not hold a press sheet hostage to a dieline that is still moving.

First sheet versus the lot

A press OK is a sheet from the run path, not a promise that every carton in a container is that sheet. Lot drift is why spot colours and a named substrate matter. Write how many faces you will hold.

If production follows weeks after the OK, board lots can move. Ask for a keep-sheet against the OK you signed. We will not invent a Delta-E window in this article.

Digital reprints of the mock-up are not a substitute for that keep-sheet. When wrap is holographic or foiled, hold a physical dummy plus the ink sheet, not the GIF.

What to put on the RFQ

Contractual proof type, spot vs process, finish map, which faces print, substrate (coated wrap, kraft, holographic), quantity band, destination. Attach a physical target if you have one.

No prices, MOQ, or guaranteed lead times in this article. Colour approval is a sheet you can hold, not a JPEG you can pinch-zoom.

Digital mock-up, wet proof, and Heidelberg production sheet are three different objects. Pick one as contractual before the knife is cut.