I. Appearance quality

外觀質量指塵埃、孔洞、針眼、透明點、皺紋、褶子、條痕、網印、毛布痕、斑點、漿疙瘩、云彩花、裂口、色澤不分歧等肉眼能夠察看到的缺陷。

Appearance quality refers to the defects that can be observed by naked eyes, such as dust, holes, pinholes, transparent spots, wrinkles, folds, stripes, screen prints, wool marks, spots, serous pimples, clouds, cracks, color and luster.

二、力學性質

2. Mechanical Properties

力學性質又稱為機械性質或強度性質，它又分為靜態強度和動態強度兩種。

Mechanical properties, also known as mechanical properties or strength properties, are divided into static strength and dynamic strength.

1、靜態強度是紙張在遲緩受力的狀況下所能接受的鼎力，又稱為終強度。它包括下面幾個質量指標：抗張強度、耐破度、撕裂度、耐折度、挺度等。

1. Static strength is the most acceptable strength of paper under the condition of slow stress, also known as the ultimate strength. It includes the following quality indicators: tensile strength, burst resistance, tear strength, flexure resistance, stiffness and so on.

2、動態強度是指紙張能禁受瞬時沖擊的強度，它反映了紙張受力后瞬時擴散的動態狀況。動態強度主要包括下面幾個指標：拆穿強度、環壓強度、緊縮強度等，這是包裝用紙和紙板重要的質量指標。

2. Dynamic strength refers to the strength of paper that can withstand instantaneous impact. It reflects the dynamic state of instantaneous diffusion of paper after being stressed. Dynamic strength mainly includes the following indicators: breakdown strength, ring compression strength, compaction strength, etc., which is the most important quality indicators for packaging paper and cardboard.

三、根本物理性質

3. Fundamental Physical Properties

根本物理性質包括紙張的定量、厚度、緊度、平滑度、硬度、松軟度、可緊縮性、吸收性等紙張為普遍的性能。

Fundamental physical properties include the most common properties of paper, such as quantity, thickness, tightness, smoothness, hardness, softness, compactness, absorbability and so on.

四、化學性質

IV. CHEMICAL PROPERTIES

紙張的化學性質包括紙張的化學組成、紙張的吸濕性、灰分、施膠度、酸堿性、耐久性。

The chemical properties of paper include its chemical composition, moisture absorption, ash content, sizing degree, acidity and alkalinity, and durability.

五、光學性質

V. Optical Properties

光學性能指白度(亮度)、色澤度、光澤度、透明度、不透明度等。對印刷紙張來說，紙張的光學性能是非常重要的，它直接影響著印刷品的質量。

Optical properties refer to whiteness (brightness), color, gloss, transparency, opacity, etc. For printed paper, the optical properties of paper are very important, which directly affects the quality of printed matter.