Why Is Surface Sizing So Important in Modern Papermaking?

Introduction

In papermaking, the quality of paper determines its final use and market value. Many people think that the formula of pulp and the forming process are the main factors, but the truth is that surface treatment plays an equally critical role. Among these processes, surface sizing stands out. It not only improves water resistance and strength but also directly affects printability and durability. Without surface sizing, paper would lose much of its overall performance. So why does surface sizing matter so much, and how does it improve different types of paper? Let’s take a closer look.

The Benefits of Surface Sizing in Papermaking

Surface sizing means applying a thin layer of sizing agent to the surface of paper after it has been formed. This simple step gives paper new properties and significantly improves performance. Its benefits include:

Better Water Resistance – Solve Ink Bleeding Issues

Raw paper fibers are porous and easily absorb water and ink, which causes blurry text, ink spreading, and even show-through. Surface sizing forms a thin hydrophobic layer that reduces liquid penetration.

For inkjet printing and high-speed offset printing, this balance is critical: the paper must absorb ink properly without excessive spreading. Sizing agents like polyvinyl alcohol (PVOH) and styrene–acrylic emulsions (SAE) help ensure sharp, clean printing results.

Stronger Surface – Reduce Dusting and Linting

Paper dust and fiber shedding are common headaches in printing. They lower print quality, damage rollers, and sometimes stop production. With surface sizing, fibers bond more tightly, improving density and strength, which reduces dusting and linting.

This is especially valuable for offset printing paper and writing paper, where large-scale printing requires stable performance and less equipment wear.

Improved Printability – Enhance Final Print Results

High-quality printing paper must not only hold ink but also maintain color richness and detail. Surface sizing regulates ink absorption so that ink adheres well without soaking in too deeply.

In four-color printing, this ensures sharper overlays and prevents muddy colors. In laser printing or photocopying, SAE-based sizing agents improve toner adhesion and prevent image fading or flaking.

Greater Physical Strength – Extend Paper Durability

Surface sizing increases fiber bonding, boosting stiffness, folding endurance, and compression strength. For book paper, this means pages resist tearing and last longer. For packaging board, it means stronger protection during shipping and storage.

Balanced Sides – Improve User Experience

Paper often has differences between its top and bottom sides, such as smoothness or absorption, known as "two-side difference." Surface sizing helps balance these differences, giving more uniform printing and writing performance.

Eco-Friendly and Cost-Effective

Sustainability is increasingly important in papermaking. Natural sizing agents such as starch are biodegradable, low-cost, and environmentally friendly. With the right sizing formula, mills can cut costs while also meeting eco-friendly paper requirements. Surface sizing thus delivers both performance and green benefits.

What Types of Paper Need Surface Sizing?

Not all papers require surface sizing, but several types benefit greatly:

Offset Paper – Used for textbooks, magazines, and books. Surface sizing improves water resistance, reduces linting, and ensures smooth, stable printing.

Writing Paper – For pens and markers, surface sizing prevents ink bleed, ensuring crisp, clean handwriting with smooth pen feel.

Packaging Paper and Paperboard – Essential for cartons, white board, and corrugated boxes. Sizing increases compression strength and resistance to water, oil, and grease, making it especially valuable for food packaging.

Currency and Security Paper – Requires high durability and anti-counterfeit features. Surface sizing improves strength, abrasion resistance, and longevity of banknotes and securities.

Premium Cultural Paper – Art paper and specialty grades benefit from sizing that enhances smoothness, gloss, and tactile quality for high-end printing.

Base Paper for Coated Grades – When applied before coating, surface sizing improves bonding and uniformity, giving coated papers like SBS board or LWC paper superior print quality and durability.

Conclusion

Surface sizing is more than just a production step—it’s the key to enhancing the overall performance of paper. From water resistance and printability to strength and sustainability, its role in modern papermaking cannot be ignored. At Golden Paper, we provide high-quality, consistently reliable paper products and tailor-made solutions for our global clients. If you’re looking for a trustworthy paper partner, contact Golden Paper and let our expertise help your business grow.