How Print Specifications Affect Postal Compliance for Mailing Campaigns

The success of high-volume mailing campaigns does not solely depend on the engaging copy and stunning visuals. When the print materials are not in compliance with postal regulations, the company might experience delays in delivery, additional mailing fees, extra reprinting expenses, and missed deadlines.

Most often, this issue can be easily solved if the company makes appropriate decisions regarding the printing in advance. The choice of paper, barcode quality, size of materials, ink used, and other printing specifications all play an important role in determining the compliance of the printed mail piece.

Why the USPS Has Specific Requirements for Printed Campaign Components

The mail delivery system handles billions of items each year using automated scanning machines. The automation has certain tolerance specifications for the item’s dimensions, reflectivity, and contrast ratio. If the item is not within those tolerance levels, then the automation fails to scan it correctly, and either rejects the item or sends it out for manual scanning that will cost more than automated scanning.

The specifications aren’t arbitrary. They reflect the actual physical and optical requirements of the equipment in the mail stream. A campaign component that was designed without reference to those specifications will often fail in ways that aren’t obvious from looking at the finished piece on a light table but become immediately apparent when a postal inspector or sorting machine encounters them at scale.

Barcode and Address Block Specifications

The most frequent area of non-compliance is the address block along with the corresponding bar codes. The bar code for automatic sorting, known as the Intelligent Mail Barcode, has certain specifications regarding bar height, bar width, spacing, and the quiet zone around the bar code. Here, print resolution plays a direct role in compliance, as a bar code printed at low resolution may feature bleeding bars, missing bars due to spaces between them being too small, or ambiguous edges of bars.

The substrate and ink combination chosen for the address side of the piece affects barcode readability as well. High-gloss substrates can create reflection interference under the infrared scanners used in some USPS equipment. Ink coverage that’s too light produces insufficient contrast for reliable reading. Both issues are addressable at the specification stage, and both become significantly more expensive to address after a production run. Catching them in a proof stage costs time measured in hours. Catching them after a run costs time measured in weeks and budget measured in full reruns.

Reflectivity and Ink Choices

The optical properties of the printed surface matter throughout the piece, not just in the address and barcode area. USPS automation uses optical character recognition to read addresses, and the contrast between the ink and the substrate needs to meet minimum standards for that recognition to function reliably.

In terms of ink selection on the address panel, this consideration is significant for selecting the proper ink color. Dark background around the address information, low ink-to-substrate contrast, certain metallic inks, and other factors may decrease the OCR readability below the accepted threshold. The expertise of the printer about combinations that may cause non-compliance is an important value proposition at the specification stage, especially in case of mail campaigns that plan to use design elements on the address panel.

Size, Thickness, and Weight Specifications

Physical dimensions and material weights interact with postal rate categories and automation eligibility in ways that affect both compliance and cost. A piece that falls into a rate category higher than planned because its finished dimensions or caliper pushes it out of the standard letter or flat category can significantly change the economics of the campaign.

The thickness is a physical measurement that is dictated by the type of substrate chosen; however, it is also impacted by the type of laminate or varnish that is chosen. A piece that meets specifications before applying the laminate may no longer be within the caliper range of its desired rate category post-laminate application.

How Inline Converting Capabilities Affect Compliance

Aside from affecting the efficiency of production through inline converting, inline capabilities also impact the quality and accuracy of the final component. The inline process offers better registration of the image on the final component compared to the offline process, especially when a component has to have a barcode or address block placed in an allotted space.

Direct mail labels applied to outer envelopes or packages are a case where that precision is particularly relevant. The label has to carry the address and barcode in a location that the mail stream equipment can reliably find and read, which requires consistent placement relative to the physical edges of the label and the surface it’s applied to. A label converter with inline die-cutting and sheeting capability can hold tighter tolerances on the finished label dimensions than one that processes those steps separately.

Getting Specifications Right Before the Run

The most effective point to address postal compliance in a mailing campaign is during the specification and proofing stage, not after the run is complete. A print partner who is experienced in producing campaign components will be able to detect any potential compliance issues at the time of the artwork proofing process, will advise on substrates and inks that satisfy both the design considerations and postal regulations, and will offer documentation regarding the compliance attributes of the finished product.  

That expertise isn’t available from every converter, and it’s worth asking about specifically before committing a large run to a vendor whose experience is primarily in non-mailing applications.

Conclusion

Compliance with postal regulations for mailing campaigns is equally a print spec problem as it is a design problem. The decisions that are taken regarding the substrate, the ink, the finishing, and the conversion process will either make sure that your large run moves smoothly through the mail stream or become the source of delay and charges.

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