Kraft Envelope Manufacturing Standards: Paper Weight, Strength and Printability

What Are Kraft Envelopes?

Kraft envelopes are made from kraft paper — a strong, unbleached or lightly bleached paper with a distinctive brown tone. They are the default choice for packaging, e-commerce shipping, document mailings and any business that wants an eco-friendly, natural look.

Kraft paper’s long-fiber composition makes it noticeably stronger than white wove paper at the same weight, which is why kraft envelopes dominate shipping and mailing applications. For a custom envelope manufacturer, kraft is also one of the most print-friendly sustainable materials — if handled with the right standards.

Kraft Paper Weight Standards

Manufacturer’s note: For most mailing applications we recommend 100–120 gsm kraft — strong enough to survive automated sorting without feeling board-like. Weights above 200 gsm generally require special folding equipment and are produced on a custom basis.

Kraft Paper Types and Grades

Printability: What You Need to Know

Kraft is absorbent and brown — three production rules apply:

1. Print colors shift — CMYK prints darker and warmer on brown kraft; convert artwork to spot colors when exact brand color matters
2. White ink is essential — for logos and bright graphics on natural kraft, white ink under-print is the industry standard
3. Higher absorbency — ink drying time is longer; presses run slightly slower, which is a minor cost factor on large runs

Standard Kraft Envelope Sizes

Strength and Sealing Standards

• Basis weight vs. burst strength — kraft at 100 gsm delivers roughly 30–40% higher burst strength than white wove at the same weight
• Sealing — kraft accepts both remoistenable gum and self-seal adhesive; self-seal is preferred for e-commerce (no licking, no moisture risk)
• Tear resistance — natural kraft’s long fibers resist edge tears; reinforced edges available for heavy contents

Finishing Options

Quality Control Checklist

1. Fiber direction — must run with the envelope length for clean folds (no cracking)
2. Fold quality — no fiber lift or crack at the flap crease (90° bend test)
3. Gumming — uniform adhesive, no bleed-through on kraft’s darker surface
4. Color consistency — natural kraft shade varies between batches; we lock a shade sample before production
5. Sampling — AQL 2.5 general inspection

Common Kraft Envelope Mistakes

• Designing CMYK artwork without white under-print — colors look muddy
• Assuming all “recycled” kraft is the same shade — it isn’t; approve a physical sample
• Using heavy board for standard mailing — postage and automated sorting issues
• Ignoring fiber direction — envelopes crack along the fold when wrong

FAQ

What is kraft envelope paper?
Kraft paper is a strong, long-fiber paper made from wood pulp (usually unbleached), giving envelopes their signature brown color and high tear resistance.

Can you print full color on kraft envelopes?
Yes, with white ink under-print for bright colors. For exact brand colors, spot-color printing is recommended.

Are kraft envelopes eco-friendly?
Natural and recycled kraft envelopes are biodegradable, recyclable, and available FSC-certified — among the most sustainable envelope options.

What weight kraft should I use for shipping documents?
100–120 gsm handles most document shipping; use 140+ gsm for heavy or rigid contents.

Do you make custom size kraft envelopes?
Yes — any size, any quantity, with custom printing. See our kraft envelope manufacturing page or request a quote.

Related Guides

• Durable Envelope Manufacturing Standards
• 9×12 Envelope Design Standards
• Custom Envelope Print-Ready File Standards