Quality Standards for Printed Products

The quality standards for printed products form a comprehensive system that covers all stages from design files to final finished products. For customers, designers, and printing houses alike, understanding these standards is crucial to ensuring the quality of printed materials.

The main quality standards for printed products can be divided into two categories: subjective standards and objective standards.

I. Objective Quality Standards (Quantifiable and Measurable)

These are hard metrics that can be precisely measured using instruments and equipment.

Color Standards

Color is the core of printing quality, requiring accurate and consistent color reproduction.

Accurate Registration: The four-color (CMYK) or multi-color plates must be perfectly aligned with no misalignment. Slight misregistration can cause blurred text or colored edges around image borders.

Accurate Hue: The color of printed products must match the approved sample or standard color swatch (e.g., Pantone color chart). Measurements are taken using densitometers and spectrophotometers.

Uniform Ink Color: Large solid color blocks or flat tints must have consistent color, with no uneven “ink streaks” or “water ripples.”

Dot Quality: Dots must be clear and sharp, without blurring, excessive dot gain, or ghosting. This is fundamental to ensuring image layering and clarity.

Printed Content Standards

Clear and Intact Text: All text must be legible, with no broken strokes, smearing, or dirt spots. Small fonts and thin lines have particularly high requirements for registration.

No Extraneous Marks: Finished products should be free of any ink spots, scratches, or fingerprints unrelated to the design.

Material and Post-Processing Standards

Paper/Materials: The paper’s weight (gsm), material, color, and glossiness must comply with contractual specifications.

Die-Cutting/Creasing: Die-cut positions must be precise, with clean cuts and no burrs; crease lines must be clear, easy to fold, and correctly positioned.

Lamination: The film must be flat, with no bubbles or wrinkles, and high peel strength.

Foil Stamping/Embossing: Patterns must be precisely aligned, with clear graphics and a smooth surface, free of smearing.

Binding:

Saddle Stitching: Book signatures must be accurately nested, staples centered, with no loose or curled pages.

Perfect Binding: Spine milling depth must be appropriate, glue application uniform, the spine flat, and pages securely bound.

Hardcover Binding: Book covers must be flat, overhangs uniform, endpapers securely attached, and the spine curvature smooth.

II. Subjective Quality Standards (Visual Perception)

These standards rely more on visual observation and experiential judgment. While not fully quantifiable by data, they are equally important.

Overall Visual Impression

Clean and Neat: The finished product should give a first impression of being clean and tidy, with no stains or defects.

Pleasing Color Harmony: Even if color measurement data falls within the allowable tolerance, the overall color matching and visual effect should align with the design intent, providing an aesthetically pleasing experience.

Rich Gradation: Transitions from highlights to shadows in images (especially photos) should be natural and smooth, with rich details.

Design Fidelity

Whether the final printed product perfectly reproduces the designer’s creativity and intent, including element layout, spacing, and size.

III. Key Quality Control Stages and Tools

To meet the above standards, the following key control points are critical in the printing process:

Pre-Press Inspection:

File Checking: Verify file resolution (300dpi or higher), color mode (CMYK), font outlining, and bleed settings. This is the foundation of all quality.

Digital Proofing: Output digital proofs for customer confirmation of content, color, and effects before official printing. This serves as an important contractual reference between customers and printing houses.

Printing Process Control:

Press Proofing: After adjusting the printing press, print samples on official paper for confirmation and signing by the customer or quality inspector. This “signed proof” serves as the color standard for subsequent mass printing.

Instrument Measurement: Continuously monitor ink density, dot gain, and registration accuracy during printing using densitometers, spectrophotometers, and magnifiers.

Light Table: Compare the signed proof with printed products under a standard light source (e.g., D50) to ensure consistent visual judgment and avoid misinterpretation due to varying ambient light.

Post-Press Inspection:Conduct 100% inspection or sampling inspection of finished products, covering all the above objective and subjective standards—especially the quality of post-processing and binding.

Quality Standards for Factory-Outgoing Adhesive Sticker Products

I. Regarding the Scope of Order Acceptance and Review

Since orders are assigned randomly, and the type of order (whether reviewed by robots or manually) is not fixed daily, it is crucial to check the process requirements in the options when submitting orders. Additionally, orders must be placed after adjusting and standardizing the submitted files. Losses caused by issues not within the review scope will not be covered by after-sales services.

Scope of order acceptance and review:

Whether the fonts in the file are outlined

Pixel density of images in the file

Consistency between the file size and the ordered size

Whether the processed content has changes

Whether the distance from effective content to the edge meets requirements

Whether spot colors are included in the layout of four-color files

Not within the effective review scope:

File content and effects

Order requirements noted in the file name

Whether the file appears blurry when the content uses four-color black with sufficient pixels

Selection of materials and processes

Whether special requirements are specifically stated or noted in the remarks section

II. Regarding Layout Standards

Common fixed layout quantities are 500, 1,000, 2,000, 3,000, 5,000, and 10,000 pieces; small-batch layouts include 100 and 200 pieces. We support production starting from 1 piece. Small quantities will be printed using digital printing, and the finished effect will differ from traditional offset printing.

For orders with quantities over 500 pieces, the number of small finished products in a combined layout during imposition is not fixed—finished products may be single pieces or multiple pieces on one sheet.

Individual cutting: If the die-cutting process requires finished products to be individual pieces of the ordered size, the “individual cutting” process must be selected.

Multiple-up layout: If the die-cutting process specifies the number of small finished products to be laid out on one sheet, the “multiple-up layout” process must be selected (a maximum of 50 small finished products can be laid out on one sheet).

Note: If “individual cutting” is not noted, after-sales services will not be provided for finished products with multiple-up layouts, and losses will not be borne.

If the “large sheet layout” process is not selected and only “maximize layout” is noted, after-sales services will not be provided for finished products that are single sheets.

III. Raw Material Quality Standards

Details of adhesive sticker material usage are as follows:

Storage requirements:

Avoid direct sunlight; protect from moisture, sun exposure, high temperature, and ultra-low temperature.

Do not store with flammable, volatile, or other dangerous goods.

Store with moisture-proof paper or film packaging. Rolled materials should be stored upright; flat sheets should be stored flat. The height of each pallet should not exceed 1m, and goods should be placed at least 10cm above the ground (using pallets).

The temperature and humidity of the storage and application environment for adhesive stickers should not be too low or too high. The optimal temperature for application and storage is 10–25°C. They can be stored for 1 year under conditions of 23°C±2°C and relative humidity (RH) 65%±5%.

Adhesion requirements:

The surface of the object to be pasted must be clean and smooth. Avoid pasting on rough or uneven surfaces, such as lime walls, cement walls, utility poles, frosted surfaces, or uneven objects. Oil, water, dust, particles, mold release agents, and other contaminants will affect adhesion and reduce bonding strength.

Paste in one direction to expel air between the label and the surface. Complete the pasting in one operation; avoid repositioning by peeling off and re-pasting if the position is incorrect.

For adhesive stickers that are too large or too small, actual pasting tests should be conducted.

Avoid contact with chemicals and solvents that can dissolve rubber or resin to prevent adhesive failure, such as ethanol, gasoline, banana oil, benzene, and formaldehyde (highly decomposing solvents).

Due to the 特殊性 of adhesive sticker products, minimize cross-season use. It is recommended that products for the current season be used within 90 days.

IV. Printing Quality Standards

Quantity: The number of printed products off the press must be sufficient; for products with post-processing, a sufficient loss margin must be guaranteed.

Registration: Error ≤ 0.1mm. Due to four-color registration on combined plates, machine vibration during operation, material expansion or contraction caused by workshop humidity, and potential human operation errors, the allowable registration error is set at 0.1mm. If the error does not exceed this range, no after-sales service will be provided; otherwise, normal handling will apply.

Color: The difference from the color values in the file must not exceed 10 units for a single color, or 10 units in total for the four colors combined. A difference exceeding 10 units compared to the standard color chart is considered unqualified. Colors of finished products ordered at different times will not be completely consistent; normal color variation exists within a single batch. Previous finished products cannot be used as color standards. Color standards are based on design draft requirements and color charts. No after-sales service will be provided for variations within the allowable range; otherwise, normal handling will apply.

V. Lamination Standards

Lamination must be correct, with a clean, flat, and non-blurry surface, good gloss, no wrinkles, no bubbles, no separation between paper and plastic, and no powder or foil marks. The lamination should be properly dried, with no damage to the surface film or paper. There should be no significant curling or warping.

VI. Die-Cutting Standards

Die-cutting requirements: Due to full-sheet printing and full-sheet post-processing, die-cutting may have a 1mm error due to unstable factors such as machine vibration during operation and paper shrinkage caused by air humidity. Therefore, before designing and submitting files, it is necessary to check whether the safe distance from the edge for effective content is sufficient—especially for files with borders. Customers must be informed in advance of the potential 1mm deviation, which may occur in any direction (up, down, left, right) due to the instability of the die-cutting blade during processing.

VII. Cutting Standards

Cutting requirements: Right-angle cut finished products may have a cutting error of 1–2mm. Before submitting files, check whether the safe distance from the edge for effective content is sufficient—especially for files with borders. Customers must be informed in advance of cutting errors. For adhesive stickers with borders less than 5mm, die-cutting is recommended; otherwise, cutting errors will likely result in uneven borders or slanted cuts.

VIII. Packaging Standards

Packaging requirements: Products with different contents must not be mixed in packaging. Packaging should be simple and neat, with no damage to wrapping paper or boxes. Packaging should be evenly distributed according to the order quantity; packages of the same file version must not vary in size, and no incorrect packaging is allowed. Special packaging requirements must be separately noted and specified in the packaging process.