Paper product classification and standard sizes - Essential knowledge for inspection, factory verification and certification

2026年4月24日

In the process of paper product trading and production, inspectors need to be familiar with the classification and standard dimensions of paper products in order to carry out inspection, factory verification and certification work. The following are common paper product categories and ISO international standard dimensions, which can be used as a reference for quality control.
I. Classification of Paper Products (Inspection and Certification Key Points)
Copy paper: 17g, standard size. Used for VAT invoices and gift packaging. Generally, it is pure white. During inspection, check the whiteness, weight, and packaging integrity.
Typing paper: 28g, standard size. Used for forms and tables. Available in seven colors: white, red, yellow, blue, green, light green, and purple. The factory inspection should verify the environmental certification of the dyes (such as non-toxic and non-fading).
Glossy paper: 35-40g, standard size. One side is glossy, used for forms, tables, and notes. It is a low-grade printing paper. During inspection, pay attention to the surface glossiness and dustiness.
Writing paper: 50-100g, both large format and standard format are available. It is used for low-end printed materials, and domestically produced paper is the most common. During inspection, the degree of sizing and smoothness need to be tested.
Double-sided coated paper: 60-180g, both large format and standard format are available. It is used for mid-range printed materials and is commonly produced by domestic, joint venture and imported companies. During certification, attention should be paid to indicators such as whiteness and opacity.
Newspaper stock: 55-60g, roll paper, standard size paper, used for newspapers. The inspection must measure the ink absorption property and tensile strength.
Carbonless paper: 40-150g, available in both large size and standard size. It has a direct reprinting function and is divided into upper, middle, and lower sheets (which cannot be interchanged). There are seven colors. It is commonly used for forms and reports. During factory audits, it is necessary to verify whether the chemical formula of the reprinting layer complies with certifications such as RoHS.
Copperplate paper:
Double copper: 80 - 400g, available in both standard and large sizes, used for high-end printed materials.
Single copper: Used for high-end printing of paper boxes, cartons, handbags, medicine boxes, etc.
During inspection, check the uniformity of the coating, glossiness and ink absorption.
Art paper ( matte copper / snow copper ): 105 - 400g, suitable for elegant and high-end color printing. Attention should be paid to the matte finish and printing properties during inspection.
Gray base white paper: 200g or above, white base with gray color, used for packaging purposes. The factory inspection should confirm the strength of the base color and the adhesion between layers.
White cardstock: 200g or above, double-sided, suitable for mid-range packaging. Certification must comply with food contact material safety standards (if applicable).
Cellophane: 60-200g, used for packaging, cartons, file bags, archival bags, envelopes. Inspection and testing of burst strength and tear strength are conducted.
Special paper: Usually imported paper is commonly used. It is mainly applied for covers, decorations, handicrafts, and high-quality printing. The inspection requires verification of certification documents and origin certificates.
The above classifications should be verified during the inspection process by checking each item according to the customer's requirements and relevant standards (such as GB/T, ISO).
II. Standard paper sizes (ISO international standard, unit: mm)
During the inspection, testing and certification process, ISO A, B, and C series sizes are commonly used. During factory audits, it is necessary to confirm whether the paper cutting equipment has calibration capabilities to ensure that the size tolerance meets the requirements.
Series A Series B Series C A0 841×1189 B0 1000×1414 C0 917×1297
A1 594×841 B1 707×1000 C1 648×917
A2 420×594 B2 500×707 C2 458×648
A3 297×420 B3 353×500 C3 324×458
A4 210×297 B4 250×353 C4 229×324
A5 148.5/148 × 210 B5 176 × 250 C5 162 × 229
A6 105 × 148.5/148 B6 125 × 176 C6 114 × 162 A7 74×105 B7 88×125 C7/6 81×162
A8 52×74 B8 62×88 C8 57×81
A9 37×52 B9 44×62 DL 110×220
A10 26×37 B10 31×44
Size Usage Description:
Series A: Basic Series, mainly used for books, documents, forms, business letters, samples, promotional posters, etc. During inspection, measure the length and width using a standard ruler. The tolerance should comply with ISO 216.
B Series: The geometric average of the A Series, without cutting. It is mainly used for paper products such as envelopes, paper clips, and file folders. During factory inspection, it is necessary to check if the die-cutting template matches the B Series.
C series: The geometric mean between A and B, commonly used for envelopes. During certification, it is necessary to confirm the size compatibility between the cover paper and the inner page paper.
Summary: In the inspection, factory verification, and certification of paper products, clearly defining the classification and standard dimensions is the fundamental task. Inspectors should be proficient in the characteristics and tolerance requirements of various paper products, and make judgments in accordance with the AQL sampling plan. At the same time, during the factory verification, it is necessary to check the calibration records and inspection reports of the supplier's paper-cutting equipment to ensure that the products meet the certification standards.