Envelope Basics: Paper

By Erin Moloney

"Envelope Basics: Paper" is part of an occasional series titled "Envelope Basics" that provides an in-depth look at all things envelope - elements, measurements, ordering tips and more*.

A variety of papers are used during the construction of an envelope. The envelope’s use will determine what type of paper works best.

It’s important to know the different types of paper available and how their weights and grades relate to your campaign.

Weighing Your Paper Optionspaper caliper

In 2016, the USPS® changed the minimum paper basis weight for automation mailings to 50 pounds or equivalent. If you are new to the mailing industry, this may sound like a different language. If you are a mailing industry veteran, you know this requirements means using at least 20 pound wove paper to qualify for automation rates.

What is basis weight and how is it calculated? Basis weight, sometimes referred to as substance weight, describes the collective weight of the fibers that make up the paper, calculated as the weight of 500 17” x 22” sheets. So an envelope made from 28# paper represents the weight of 500 17” x 22” sheets of that paper and not the envelope itself.

Caliper is another way to determine basis weight. It’s the measurement of the thickness or caliper of the paper, and corresponds with basis weights:

SUBSTANCE WEIGHT NOMINAL CALIPER (mils)
20 4.2 - 4.4
22 4.5 - 4.7
24 4.8 - 5.1
28 5.4 - 5.7

Making Grades with Paper

There are six main types of paper grades used in envelope production.

  • Wove – Wove has short fibers, prints well, has a smooth appearance and is an economical option. It’s available in many weights and colors, and in its original form is known as Bright White paper (with a brightness level of 92). This is a popular paper for statement mailers and direct mail alike.
  • Surfaced Enhanced White Wove – this paper is often referred to as calendarized paper, which is used with offset lithographic printing. Surfaced enhanced white wove is very smooth and ideal for heavy ink designs.
  • Kraft – Kraft paper is strong, has longer fibers than wove and is commonly seen in brown stock. However, kraft paper doesn’t print well due to its long fibers and would not be ideal for complex graphics or 4-color ink processes.
  • Recycled – looking to create a green envelope? Using recycled papers for your envelopes is a great way to improve your sustainability. Most commonly, recycled papers used in envelope production are made up of 10 percent to 30 percent post-consumer content.
  • Specialty – specialty papers are available in many colors, finishes, textures and weights. They are ideal for direct mail envelopes due to their intriguing features, yet can come at a higher price tag.
  • Tear-resistant – this paper is almost indestructible and won’t tear under typical applications. It is also often water and moisture resistant. Tyvek and Protec envelopes are made from tear-resistant paper.

The paper you choose could help your mail succeed. Contact us today to talk about which paper options are right for you.

*This blog is intended for informational purposes only. Exact envelope and/or print specifications should be discussed in detail with your Sales Representative.