Sample approval is one of the most useful ways to prevent avoidable disagreements in custom paper-packaging orders. An attractive sample can still be unsuitable for production if the buyer never defined the paper structure, dimensional tolerances, conditions of use or inspection method. This guide explains the decisions to settle before authorizing a production order. It is a procurement framework, not a claim that a particular factory has already performed every test described here.
1. Create one specification reference
Before reviewing samples, collect a drawing or representative physical sample, destination market, expected end use, operating conditions, print artwork, forecast and delivery requirements. Mark each requirement as either fixed or open for supplier recommendation. Assign a revision identifier to the approved specification; this makes it easier to trace changes after a proof or prototype has been accepted.
- Dimensions: open and folded sizes, gusset, sheet geometry or roll diameter, plus measurement method and tolerance.
- Materials: base paper grade and grammage, coating or barrier structure, ink and adhesive requirements where relevant.
- Use: packed contents, service temperature, moisture and grease exposure, handling method and expected contact duration.
- Appearance: print artwork, color reference, branded positioning, visible fold lines and permitted variation.
- Delivery: unit packing, shipping market, carton or pallet requirements and expected ordering frequency.
2. Approve design, materials and finished form separately
A PDF proof can establish artwork layout but cannot prove that a folded, filled bag fits its intended application. A flat coated-paper sample can help assess material structure but cannot by itself establish how a converted bag’s seams, handles or closure perform. Specify what each approval stage is intended to confirm.
| Approval stage | Buyer examines | What it does not automatically prove |
|---|---|---|
| Artwork proof | Text, symbols, dimensions, print side and brand placement | Final bag geometry, ink suitability or production color stability |
| Paper or coating sample | Specified material construction and relevant test data | Finished-bag seams, handle strength or liquid containment |
| Unprinted converted prototype | Shape, bag opening, gusset, folds, sample fit | Approved print reproduction or destination-market compliance |
| Printed preproduction sample | Appearance on real paper, assembled form and agreed checks | All future production lots without continuing acceptance controls |
| Actual equipment trial | Converter handling or sealing on named buyer equipment | Universal compatibility across different machinery and settings |
3. Match testing to the proposed paper product
Different products call for different acceptance criteria. For kraft takeaway carrier bags, a filled-load and handle assessment may be important. For grease-resistant snack bags and food wrapping sheets, define the expected food, exposure conditions and applicable material evidence. For airsickness bags, a finished-bag containment and closure trial matters if liquid performance is a purchasing requirement. For PE-coated rolls, a machine trial can expose winding, blocking and conversion difficulties.
When a supplier provides a test report, compare the identified sample, test date, method and construction with the product that will actually be ordered. A report for one PE-coated white kraft sample, for example, cannot establish that every printed paper bag is suitable for food contact.
4. Define how an approved sample becomes an acceptance standard
Ask what the approved reference will be: a signed drawing, approved material specification, retained physical sample, print reference or a combination. Define inspection sample quantities and pass/fail criteria with the supplier. A buyer should record which changes require a new sample and approval.
- Material revision: new paper grade, coating, adhesive or ink system.
- Geometry revision: opening, gusset, fold pattern, liner size or roll winding.
- Print revision: wording, graphic coverage, color, artwork placement or warning instructions.
- Use revision: changing from dry food to oily food, from dry waste to liquid exposure, or from serving to heating.
5. Prepare the final sign-off record
A practical approval record names the buyer, supplier, product and revision; the agreed sample reference; the dimensional and material specifications; the specific approved tests; print-proof revision; packaging format; and the people responsible for approval. It should also state what remains conditional rather than implying that missing documents have been received.
Buyer questions before signing
Is a concept picture enough? No. Visuals are useful for discussing form and branding but cannot demonstrate manufacturing feasibility, exact specifications or test performance.
Does an ISO or FSC certificate replace sample testing? No. Management systems, Chain of Custody and finished-product testing address different questions; review each document’s scope.
Can the factory change paper grammage after a sample is approved? Agree change control in writing. A substitution may change dimensions, folding, print appearance and performance, so determine whether reapproval is required.
Related sourcing resources
Use the manufacturing process guide for the broader workflow, the materials and flexographic printing guide for specifications, and the quality evidence page for documentation scope. Prepare a copyable RFQ worksheet to share a consistent brief through a verified sales channel when available.
Specifications, test methods and claimed capabilities must be confirmed for the exact proposed order. This guide does not establish approvals or legal compliance for any product or market.
This article offers general procurement guidance, not a guarantee of particular manufacturer capability or compliance. Confirm requirements, materials and tests against a written specification.