Short answer: specify brand colours as Pantone spot inks, let photographs and gradients run as CMYK process, and expect the number of print stations — not the artwork file — to drive cost. A four-colour logo printed as CMYK on film will drift; the same logo as a spot ink reproduces the same way on the second order as on the first.
Why film is not paper
Flexible packaging is printed on plastic film, and almost always with a white layer underneath. Three consequences follow, and they explain most colour surprises:
- Ink sits on a white underprint, not on the film. Opacity is excellent, but the white itself has a shade, and it shifts every colour printed over it.
- The substrate changes the read. The same Pantone looks different on kraft, on clear film, on metallized film and on foil. This is physics, not a printing defect.
- Clarity is lower than paper. Fine gradients and small type behave differently — a smooth 2 % gradient on a coated paper may band on film.
Spot colour vs process colour
| Pantone (spot) | CMYK (process) | |
|---|---|---|
| How it is made | A single premixed ink | Four inks screened together |
| Accuracy | Very high; repeatable order to order | Approximate; needs more control |
| Brand colour match | Excellent | Often visibly off, especially greens, oranges, deep blues |
| Photographs and gradients | Not suitable | Designed for this |
| Cost | One print station (and, on gravure, one cylinder) per colour | Four stations regardless of how many colours appear |
| Best use | Logos, brand blocks, flat colour, text | Imagery, gradients, complex illustration |
The practical answer for most packaging is a hybrid: three or four process stations for the photograph on the front panel, plus spot stations for the logo and the brand colour block.
How many colours can you afford?
Each spot colour needs its own station. Gravure presses commonly run up to eight or ten colours, with high-end machines reaching twelve — which is why "12-colour rotogravure" appears in premium coffee and specialty packaging. Every additional colour adds a cylinder (or plate), a station and setup time, so a 9-colour design is not a small increment over a 6-colour one.
For gravure, cylinders are a one-off cost tied to the artwork. Change the design and you pay again. That single fact drives the entire commercial logic of packaging: it is why brands standardise a design for years, and why minimum order quantities exist at all.
What to put in the brief
- Pantone references, not RGB values. A hex code means something on a screen and nothing at a press. Give the Pantone number and, where relevant, the coated/uncoated variant.
- Which elements are spot and which are process. Mark them on the artwork or in a colour list. "Logo = Pantone 2935 C spot" removes all ambiguity.
- The substrate. A colour approved on white film can look wrong on kraft. Approve on the material you will actually print.
- An acceptable tolerance. Colour is a range. A common specification is ΔE ≤ 3 for spot colours and ΔE ≤ 5 for process builds; agree it in writing and state the measurement conditions.
- Existing print to match. If you have a carton, a label or a previous bag, send a physical sample — not a photo of it.
Approving colour without flying to the factory
Screens lie in a specific, predictable way: they are backlit, they cannot show metallic or matte, and every monitor is calibrated differently. Three practical substitutes:
- A physical proof on the actual structure, approved under daylight (D50 is the print standard) and again under shop lighting.
- Pantone chip comparison on the proof — hold the chip against the printed area, in the same light.
- A retained reference bag. Keep one signed bag from the approved run. Every future order is matched against that, not against a file.
Common failures and their cause
- "The green is too blue." A CMYK conversion of a brand green. Fix: make it a spot.
- "It looked right on the proof." The proof was a digital print on paper. Fix: proof on the real structure.
- "The second order is different." Ink batches and substrate lots vary. Fix: a retained reference and a written tolerance.
- "The logo is fuzzy." Small reversed-out text on film. Fix: increase size or convert to positive print.
What we do
Xiangyi Packaging prints on 12-colour rotogravure, which is enough stations for a photographic front panel plus multiple spot brand colours in one pass. We ask for Pantone references up front, mark spot versus process on the artwork, and proof on the structure you are ordering rather than on paper. Minimum order is 10,000 pieces for multi-layer barrier pouches and 5,000 for simpler printed bags.
Every artwork revision that changes the colour list needs new cylinders; agree the final colour list before plates are cut.
Next step: send your logo with its Pantone reference and a photo of any existing packaging you want to match. We will tell you which elements should be spot, which should be process, and what the colour count does to the unit price. Ask for a colour plan · Product range
Frequently asked questions
Can CMYK reproduce a Pantone exactly?
Usually not. Process printing approximates; some Pantones — bright oranges, saturated greens, deep blues — are outside the CMYK gamut on film entirely.
Does one more colour really cost much?
It costs a print station, a cylinder and setup time, and on gravure the cylinder is a one-off tied to that artwork. The incremental unit price is modest; the changeover cost is not.
Why does my colour look different on kraft?
Kraft is not white. Unless the printer lays down an opaque white underprint, the paper shade shows through and shifts the ink.
Can you match a colour from a photo of our old bag?
A photo is a starting point, not a reference. Send a physical sample or the Pantone number; those are the only two things a press can be held to.