If you’ve ever received a postcard with unsightly black or gray streaks across the front, you’re not alone. Smudges on USPS postcards are a common frustration for businesses and individuals alike. Whether you’re sending marketing postcards or personal greetings, those marks can make your mail piece look unprofessional. Let’s break down why this happens—and, more importantly, how you can prevent it.
Why Do USPS Postcards Get Smudged?
1. High-Speed Sorting Equipment
The USPS processes millions of postcards daily through automated sorting machines. These machines use rollers, belts, and ink-jet spray technology to apply barcodes. The friction and contact can sometimes cause scuffing or streaking, especially on glossy surfaces.
2. Ink from Postal Barcodes
As part of automation, the USPS applies an Intelligent Mail Barcode (IMb). The ink is often fast-drying, but on coated or glossy stocks, it can smear if the postcard rubs against another piece of mail.
3. Paper and Coating Type
Not all postcard paper is created equal. High-gloss UV-coated postcards look vibrant, but the slick surface can attract smudging when run through high-speed machines. Matte or uncoated stocks tend to resist smears better.
4. Handling During Transport
Mail doesn’t just travel through machines—it’s also stacked, bundled, and transported. Along the way, postcards rub against each other, sometimes transferring ink or causing abrasion.
How to Avoid Smudges on USPS Postcards
1. Add a Finish for extra protection
Matte or Satin Coating: Provides protection without being too slick.
Aqueous Coating: A thin water-based coating that adds durability while staying USPS-friendly.
2. Design with USPS Automation in Mind
Leave the barcode clear zone free of dark, glossy, or heavy ink coverage. This minimizes the chance of smears where USPS prints its barcode. Adding a barcode will also reduce the number of a machines the mail piece runs through reducing the chances of smudging. Return mail typically has more smudging as it will run through multiple machines
Final Thoughts
Smudges on USPS postcards are usually a byproduct of high-speed automation and paper finish—not a reflection of poor printing quality. The good news? With the right stock, coating, and design adjustments, you can dramatically reduce the chances of streaking.
At Action Mail, we specialize in printing and mailing postcards that not only look great but also arrive in your customers’ hands without the mess. If you’re planning a postcard campaign, we’ll help you choose the right paper and finish to ensure a clean, professional presentation.