Design File Specifications
Provide original vector source files in formats such as AI, CDR, and EPS, and convert all texts to outlined paths to prevent font missing and content distortion during printing. Bitmap materials must have a resolution of no less than 300 dpi, preferably in high-definition PNG or TIFF formats; screenshots and compressed blurry images are strictly prohibited. Designs shall be created based on finished product dimensions, with a 3–5 mm bleed allowance, and clearly mark the exact printing position, centering alignment, and margins of the logo. Redundant layers, hidden elements, and invalid masks shall be removed to enable direct plate making at the factory, eliminating issues like blurred graphics, misaligned text, and white gaps from cutting at the source, and ensuring sharp logo edges and accurate overall proportions. custom shipping bags with logo demand standardized, error-free source files to lay a solid foundation for high-quality printing.
Color Printing Standards
All printing shall adopt the CMYK color mode; direct use of RGB color values that cause severe color differences is forbidden. For brand standard colors, the corresponding PANTONE color number may be specified with written confirmation. Digital or plate proofs must be produced and signed off by both parties as a color reference before mass production. When printing light-colored logos on dark bag bodies, a white base layer shall be printed first to avoid background show-through, grayish tint, and insufficient color saturation. Color differences within the same batch shall be controlled within an acceptable range to guarantee consistent color across the entire order and compliance with brand visual standards. This step is critical to stabilizing the visual effect and ensuring every part of the production meets the preset quality for custom shipping bags with logo.
Printing Process Compatibility
Select suitable processes including screen printing, offset printing, flexographic printing, thermal transfer, and direct digital printing according to different materials like non-woven fabric, paper, plastic, and canvas. Cost-effective screen printing is suitable for simple text and solid color blocks, while offset or digital printing is preferred for complex gradients and high-definition patterns to avoid ink breakage on fine lines and halftone dot blurring. For high-end customization, gold/silver foil stamping, UV varnishing, and embossing/debossing can be added to enhance logo texture. The process selection shall balance pattern complexity, production volume, and finished effect, integrating aesthetics and production feasibility.
Environmental and Fastness Requirements
Use odorless inks that meet national environmental standards and export requirements such as RoHS and REACH. Food-contact bags must use food-grade eco-friendly inks free of heavy metals and harmful solvents. The printed layer of finished products shall have excellent adhesion, with no color fading, ink peeling, or sticking after folding, kneading, and daily friction. Washable bags made of canvas, linen, and similar materials must resist fading, bleeding, and cracking after repeated washes, ensuring safe and durable use.
Finished Product Inspection Standards
The positioning deviation of logo printing shall not exceed 2 mm. Defects including missing prints, wrong prints, misalignment, stains, ink splatters, and color registration errors are not allowed. Edges of graphics and text shall be sharp, with no rough edges, white gaps, or ghosting. The color of the entire batch shall be uniform with no visible color difference from the approved sample. Subsequent processes such as cutting, sewing, and punching must not damage or cover the printed area. Finished products shall be free of smudges, blurs, and scratches, with consistent logo position, size, and color on every unit, fully meeting the appearance and quality standards for bulk delivery of custom shipping bags with logo.https://www.heyuprinting.com/paper-bag/shopping-paper-bag.html