Eye-Protection Grade Evaluation for Exercise Books: Standards, Testing Methods, and Grading Criteria

Eye-protection grade evaluation is a laboratory-based assessment of the optical, printing, and material characteristics of student exercise books that influence visual comfort, writing fatigue, and myopia-related risk factors. Performed by accredited third-party laboratories against frameworks such as GB 40070-2021 and QB/T 5194, the evaluation measures paper D65 brightness, fluorescent whitening agents, print contrast, opacity, gloss, and ruling precision, and converts the results into a tiered eye-care grade. This guide explains the sampling plans, testing items, measurement methods, and grading logic that manufacturers, publishers, schools, and procurement buyers rely on to substantiate eye-friendly claims.

Technical Overview

Exercise books remain the primary writing medium for primary and secondary school students, who may spend several hours per day performing near-distance work on ruled or gridded pages. Because the eye interacts directly with the paper surface during this work, the optical behavior of the page has a measurable influence on visual load. Excessively bright or optically brightened paper produces dazzle and scattered glare, low print contrast and imprecise ruling force the eye to work harder to track lines, high surface gloss creates specular reflections, and poor opacity allows show-through from the reverse side, all of which contribute to reading and writing fatigue.

Eye-protection grade evaluation is a systematic testing and scoring program that quantifies these product-side risk factors. It combines two layers of assessment. The first layer is compliance verification against mandatory hygienic and product requirements, principally GB 40070-2021, the Chinese national standard specifying myopia-prevention hygiene requirements for children's study supplies, supported by QB/T 5194 for exercise book construction and GB 21027-2020 for chemical safety. The second layer is a weighted performance scoring model that assigns the product to an eye-care grade, commonly expressed as Grade A, Grade AA, and Grade AAA, or an equivalent multi-level scheme, with the top grade representing the highest standard of visual ergonomics. Any failure of a mandatory item blocks grading regardless of the composite score, so a graded product is by definition a compliant product.

The evaluation draws on the following reference framework of standards organizations:

• GB 40070-2021 — Hygienic requirements for myopia prevention of study supplies for children and adolescents, covering textbooks, teaching aids, exercise books, and reading materials.
• QB/T 5194 — Industry standard for school exercise books, covering ruling dimensions, dimensional tolerances, binding quality, and writing performance.
• GB 21027-2020 — General safety requirements for student supplies, covering migratable elements and other chemical safety parameters.
• ISO 2470-1 / GB/T 7974 — Measurement of diffuse reflectance factor (D65 brightness) of paper, board, and pulps.
• ISO 2471 / GB/T 1543 — Determination of opacity (paper backing method).
• GB/T 27741 — Determination of fluorescent whitening agents in paper and board.
• GB/T 8941 / ISO 8254 — Measurement of specular gloss of paper and board.
• GB/T 10739 / ISO 187 — Standard atmosphere for conditioning and testing of paper and board samples.

Testing Samples

Product Categories Covered

The evaluation applies to the full range of student exercise books and workbook-style products, because each ruling type presents a distinct contrast and line-tracking task for the eye:

• Horizontal-line ruled writing books for general coursework and composition.
• Squared and grid-ruled mathematics exercise books.
• Pinyin three-line and four-line ruling books for language learning.
• Field-grid and lattice character-practice books for handwriting training.
• Dictation books, draft books, and scratch-paper pads.
• Workbook-style exercise books combining printed questions with answer-writing space.

Sampling Plan

Samples are drawn randomly from a defined production batch, typically following statistical sampling principles consistent with GB/T 2828.1 (ISO 2859-1). A common practice is to collect books from at least three positions of the production run, such as the beginning, middle, and end, in order to capture variation in paper reels, ruling ink, and press conditions. For a type evaluation, a minimum quantity of finished books is secured together with retained samples of the paper substrate so that both the blank paper and the printed page can be characterized.

Conditioning and Specimen Preparation

Paper is a humidity-sensitive material, so all specimens are conditioned in a standard atmosphere of 23 ± 1 °C and 50 ± 2 % relative humidity for at least 24 hours prior to measurement, in accordance with GB/T 10739 (ISO 187). Specimens are protected from ultraviolet radiation and strong light between sampling and testing, since optical brighteners can degrade under UV exposure. Only clean, crease-free, defect-free sheets are selected, and a minimum of ten specimens is prepared for each optical test item to support statistical treatment of the results. Both paper sides are identified and measured where the two sides differ optically.

Testing Items

The test program addresses the optical, print-geometric, and functional properties that determine how visually demanding the page is during sustained writing. Typical testing items are as follows:

• Paper D65 brightness — an upper limit (not exceeding 85 % under GB 40070-2021) prevents dazzle from an over-bright page, while a practical lower bound ensures the page retains sufficient luminance for legible print and ruling contrast.
• Fluorescent whitening agent contribution — optical brighteners raise apparent brightness by converting UV energy into blue emission, increasing glare and cool tinting; detectable fluorescence places a strict ceiling on the achievable grade.
• Print contrast and ruling optical density — ruling lines must be dark enough to guide the eye and handwriting but not so heavy that they dominate the page.
• Specular gloss of the paper surface — a measure of mirror-like reflection that quantifies glare under desk and classroom lighting.
• Opacity — resistance to show-through, so writing and ruling on the reverse side do not interfere with legibility.
• Chromaticity and tint — neutral or mildly warm, cream-toned pages generally score more favorably than cold blue-white surfaces.
• Ruling geometry — line spacing, line width, grid dimensions, baseline deviation, and positional tolerances measured against the specifications of QB/T 5194.
• Erasability and ruling fastness — the ruling must withstand repeated erasing without fading, flaking, or ghosting, since erasure residue and damaged lines degrade the visual field of the page.
• Writing surface performance — ink feathering, strike-through, and pencil glide, which support overall writing ergonomics.
• Complementary safety screening — migratable elements and formaldehyde verification in accordance with GB 21027-2020, reported alongside the optical grade.

Testing Methods

Brightness and Luminance Factor

D65 brightness is measured with a diffuse/0° reflectance spectrophotometer using the D65 illuminant and a calibrated white reference standard, following ISO 2470-1 and GB/T 7974. Measurements are taken with the UV component fully included, and the fluorescent contribution is isolated using a UV-cut-off filter so that the true, non-fluorescent reflectance of the sheet can be separated from the optically brightened appearance. Multiple positions across each specimen are measured and averaged, and measurement uncertainty is reported with the result.

Fluorescent Whitening Agent Determination

Fluorescence is assessed in two complementary ways. The differential reflectance method compares brightness with and without UV excitation to quantify the fluorescent component directly on the finished page. Where quantification of agent content is required, the extraction-spectrophotometric procedure of GB/T 27741 is applied to the paper substrate. Grading schemes typically treat any significant fluorescent contribution as a gating deficiency or apply a severe score penalty, because optically brightened pages are a principal source of dazzle in student stationery.

Print Contrast and Ruling Density

Contrast between the ruling lines and the paper substrate is determined by reflectance photometry or densitometry. The reflectance of the printed ruling is compared with the reflectance of the adjacent blank paper, and the contrast value is calculated as the normalized difference between the two. At least ten representative lines or line segments are measured per sample. The objective is not maximum contrast but an optimal window: lines that reliably guide writing without creating a harsh, high-striction visual pattern on the page.

Specular Gloss

Surface gloss is measured with a glossmeter at the 75° geometry specified in GB/T 8941 and ISO 8254, the standard angle for paper grades. Low gloss values indicate a matte surface that scatters incident light and minimizes glare from desk lamps and classroom luminaires, which is the preferred condition for eye-care products.

Opacity

Opacity is determined in accordance with ISO 2471 and GB/T 1543 by comparing the reflectance of a single sheet backed by a black body with the reflectance of a thick stack of the same paper. High opacity prevents show-through of ruling and handwriting from the reverse side, preserving the legibility of the working page.

Dimensional and Print Inspection

Ruling geometry is inspected with calibrated measuring microscopes, measuring projectors, or image-analysis systems. Line spacing, line width, grid dimensions, and positional deviation are evaluated against the tolerances of QB/T 5194, and the uniformity of line spacing across the page is assessed because irregular spacing disturbs handwriting rhythm and line tracking.

Erasability Trial

A standardized erasing test is performed in which defined pencil strokes are executed under a controlled load and removed with a standard eraser for a specified number of cycles. The residual marks are assessed visually and instrumentally, and the condition of the ruling lines after erasing is graded to confirm that the page withstands the real correction behavior of school-age users.

Scoring and Grading Logic

After testing, the results are processed through a two-step model. First, mandatory items from GB 40070-2021, QB/T 5194, and GB 21027-2020 act as gates: any nonconformity terminates the grading process. Second, the qualifying results are normalized and combined with weighting factors, for example placing the greatest weight on brightness window compliance and fluorescence, followed by contrast, ruling precision, opacity, gloss, and erasability. The composite score maps the product to its grade, such as Grade A for basic eye-care performance, Grade AA for advanced performance, and Grade AAA for premium performance across all parameters.

Applications

Eye-protection grade evaluation supports stakeholders across the full product lifecycle:

• Product development — paper mills and book manufacturers use graded feedback to select FWA-free furnish, tune brightness to the optimal window, and adjust ruling ink density and line geometry before mass production.
• Factory quality control — incoming paper reels, ruling ink, and finished books are verified batch by batch to maintain the certified grade over time.
• Certification and labeling — a verified grade substantiates eye-protection claims in retail, e-commerce listings, and packaging, reducing the risk of misleading advertising.
• School and government procurement — education authorities and schools increasingly require evidence of compliance with GB 40070-2021 and a recognized eye-care grade in bidding documents.
• Market surveillance — regulatory monitoring programs use the same test items to screen products sold with eye-friendly claims.
• Export compliance — because brightness conventions differ between ISO, EN, ASTM, and JIS measurement systems, the evaluation provides the data needed to demonstrate equivalent performance in international markets.

FAQ

What paper brightness counts as eye-protective?

GB 40070-2021 caps the D65 brightness of study paper, including exercise book paper, at 85 % to prevent dazzle from over-bright pages. Beyond this mandatory limit, grading schemes apply their own scoring, and the highest grades are typically awarded to pages in a moderate brightness range with a neutral or mildly warm tone, where print contrast remains comfortable rather than harsh.

Are fluorescent whitening agents prohibited in exercise books?

Fluorescent whitening agents are strongly discouraged in eye-care graded products because they inflate apparent brightness and increase glare through UV-to-blue conversion. The evaluation quantifies fluorescence using ISO 2470-1 differential reflectance and GB/T 27741 methods, and detectable fluorescent contribution generally prevents a product from reaching the upper grades even when other parameters perform well.

Does a top grade guarantee that myopia will be prevented?

No. The grade certifies that product-side visual risk factors, such as dazzle, glare, poor contrast, and show-through, have been minimized. Myopia prevention also depends strongly on user behavior, including reading distance, ambient lighting, outdoor activity, and regular visual breaks, which no paper product can substitute for.

How does grade evaluation differ from ordinary quality inspection?

Ordinary inspection is a pass-or-fail check against fixed limits. Grade evaluation starts from the same compliance verification but continues with a weighted scoring of optical and print-quality parameters, producing a tiered result that allows products to be compared with one another and communicated to consumers as a level of performance rather than a simple acceptance decision.

How often should the evaluation be repeated?

For certification purposes, a full type evaluation is normally repeated at defined intervals, such as annually, or whenever the paper furnish, ruling ink, coating, or production process changes significantly. For production control, manufacturers typically verify the key optical parameters on every batch to ensure the certified grade remains valid.

Do cream-colored papers automatically receive the highest grade?

No. Paper tint is only one scored parameter. A cream-toned page must still meet the brightness limits, demonstrate adequate ruling contrast, sufficient opacity, low gloss, accurate line geometry, and durable erasability before it can qualify for a premium grade. Tone alone does not determine the outcome.