How to Choose High-Quality Kraft Paper?

How to Choose High-Quality Kraft Paper?

Color and Uniformity: High-quality kraft paper typically displays a natural, soft beige or light brown color with even distribution and no noticeable color differences or spots.  Excessively pale paper may indicate over-bleaching, which weakens durability, while uneven coloring or dark/yellow spots suggest production flaws.

Smoothness and Texture: Feel the paper’s surface.  Quality kraft paper is moderately smooth yet retains a subtle texture, balancing aesthetics with printability.  Overly rough surfaces may blur prints, while overly smooth ones hinder ink adhesion, causing fading.

Impurities and Damage: Check for dust, fiber clumps, or other impurities, as these weaken the paper and increase tear risk.  Avoid sheets with holes, cracks, or tears, especially for packaging or printing where integrity is critical.

How to Evaluate Kraft Paper Quality?

1.  Visual Inspection

Ensure uniform color without obvious variations.  Under bright light, high-quality paper shows no dark spots, streaks, or mottling, indicating consistent weight.

Food-grade kraft paper has a brightness level of 83-85%, slightly yellowish.  Overly bright paper may contain excessive fluorescent agents, unsafe for food packaging.

Check for flaws like linting, pinholes, or streaks.  Compare smoothness by touch with a sample.

The surface should be flat and smooth, free of wrinkles, bubbles, or foreign particles.

2.  Physical Performance Tests

Folding Test: Fold the paper 3–5 times.  No visible cracks mean good folding endurance.

Tensile Test: Stretch the paper.  Longitudinal stretch rate below 5% is qualified;  transverse tears should show jagged edges, not straight breaks.

Weight Measurement: Use calipers or tools to measure grammage.  Higher weight indicates denser fibers and greater durability.