Digital Printing

Four preparations required before sending the design file to the printing factory: bleed, resolution, color mode, and fonts—the issue where clients most often make mistakes is failing to convert fonts to outlines.

📅 2026-09-18 ✍️ Wuxi Lexiang Printing & Packaging ⏱ 3min read

💡 💡 At a Glance

When a customer’s designer sends an AI file to the printing plant without converting the fonts to outlines, everything reverts to SimSun, delaying the production schedule by 5 days and causing a loss of RMB 8,000. This article details the 4 preparations required before sending a design file to the printing plant—3mm bleed / 300dpi resolution / CMYK color mode / font outlining. The most common mistake is failing to convert fonts to outlines—when the printing plant opens the file, all fonts become SimSun, ruining the overall design.

In August 2024, a client specializing in cosmetics packaging contacted us. The client’s original words were:

“We sent the AI files prepared by our designer to the printing plant, but when the printer opened them, all the fonts had changed to the default [Song typeface]—it turned out that the designer had not converted the fonts to outlines. The entire batch of designs had to be redone, delaying the production schedule by 5 days and causing a loss of 8000 RMB.”

This is a genuine prepress preparation error. Before accepting a digital printing order, a packaging printer must clarify 4 prepress preparation requirements.

First preparation: 3mm bleed

What is bleed? The design file should extend 3mm beyond the actual printed size to provide a margin for cutting.

Why 3mm? The printing industry standard is 3mm bleed (some printing plants require 5mm). Less than 3mm may result in white edges; more than 3mm increases paper costs.

The 3 costly mistakes customers are most likely to make:

  • Bleed not set: The edges of the design file exactly match the print dimensions, making white edges likely during trimming
  • Set the bleed to 5mm: wastes paper and increases costs, with no benefit
  • Bleed on all sides: Bleed must extend beyond all 4 edges, not just one side

    • Printer's recommendation: Upon receipt of the design file, the printer should check the bleed as soon as possible. Files without bleed settings must be resubmitted by the customer with the bleed configured.

    Second preparation: 300dpi resolution

    What is resolution? The number of pixels per inch. Printing requires ≥300dpi. Images below 300dpi will appear blurred.

    The 4 resolution mistakes customers are most likely to make:

  • From a webpage screenshot: The webpage image has a resolution of only 72dpi, so it will appear blurry when printed
  • From the video screenshots: The video frame resolution is only 72-96dpi, so it will appear blurry when printed
  • Bitmap export from AI software: Bitmaps exported from AI software default to 72dpi and must be manually changed to 300dpi
  • Mobile phone photos: Although mobile phone photos have a high resolution (4000x3000), they default to 72dpi and need to be changed to 300dpi

    • Printer's recommendation: After receiving the design file, the printer should use AI software to check the image resolution. For images below 300dpi, the customer should be required to provide a high-resolution version.

    Third Preparation: CMYK Color Mode

    What is a color mode? CMYK (cyan, magenta, yellow, and black) is used for printing, while RGB (red, green, and blue) is used for screen displays. RGB files sent by customers must be converted to CMYK by the print shop, but this conversion may result in color differences.

    The 4 color-pattern mistakes customers are most likely to make:

  • RGB Direct Printing Factory: The color difference between the on-screen display and the printed output is 10-20%
  • RGB spot colors were used: RGB spot colors cannot be converted to CMYK, resulting in incorrect colors
  • CMYK spot colors were used, but no Pantone number was specified: Pantone numbers serve as color standards; without them, the printing house cannot match the colors accurately.
  • Uses RGB black: RGB black converts to CMYK as [four-color black]—all 4 inks are printed, wasting ink and causing blurriness

    • Printer's recommendation: The customer's design file must use CMYK mode. Spot colors must specify the Pantone number (e.g., Pantone 1655 C). For black, use solid black (K 100%) rather than four-color black (C 100% M 100% Y 100% K 100%).

    Fourth Step: Convert Text to Outlines

    What is converting text to outlines? Converting the fonts in a design file into paths/curves so that they display correctly on any computer.

    The 4 font-to-outline mistakes customers are most likely to make:

  • Fonts not converted to outlines: When the printing plant opens the file, the fonts change to the default [SimSun], ruining the entire design
  • Some fonts converted to outlines: some fonts are converted to outlines while others are not, resulting in inconsistent display
  • The text is still incorrect after conversion to curves: Some fonts become distorted after conversion to curves and need to be checked again
  • A non-system font was used: The client used a non-system font (such as Arphic Kaiti), but it was not installed on the printer’s computer, so it was displayed in the default font

    • Printer's recommendation: The customer's design file must convert all text to outlines. In the AI software, select 【Type】 → 【Create Outlines】 to convert text to outlines with one click.

    4 Iron Rules for Printing Factories When Receiving Design Files

  • Check 4 things immediately upon opening the design file: bleed / resolution / color mode / converting fonts to outlines
  • If any item fails, require the customer to modify it: Do not settle for something that can only be done with difficulty—products made this way will have poor quality
  • Quotation is provided only after all 4 preparations are completed: avoiding the costs of repeated revisions at a later stage
  • Produce and approve the digital sample: Once all 4 preparations are complete, produce a digital sample for the customer to confirm the color and effect

    • The 3 Comprehensive Mistakes Customers Are Most Likely to Make

  • Artwork crosses boundaries, is blurry, and has not had its fonts converted to outlines: Failing all 3 checks is the most common mistake made by novice designers
  • RGB Mode + On-Screen Colors: Customers design in RGB and evaluate colors on screen, resulting in significant color differences after printing
  • Uses materials downloaded from the Internet: downloaded materials may have low resolution and may infringe copyright

    • 4-Point Prepress Checklist

    Before sending the customer’s design file to the printer, it is recommended to use this checklist for a self-inspection:

  • Bleed: 3mm on each of the 4 sides? ✓/✗
  • Resolution: All images ≥300dpi? ✓/✗
  • Color Mode: CMYK? ✓/✗ Pantone numbers available for spot colors? ✓/✗
  • Convert fonts to outlines: Have all fonts been converted to outlines? ✓/✗

    • All 4 items must be checked ✓ before sending to the printer; otherwise, the job will be rejected and require rework.

    Further Reading

  • Comparison of 3 Prepress File Formats: AI / PDF / CDR — A Real Case of 3 Days of Rework Caused by Sending the Wrong Format
  • Insufficient file resolution causes 3 types of printing failures: The [high-resolution images] sent by the client are actually only 72 dpi
  • Pantone vs CMYK vs Digital RGB: The Real Differences Among 3 Color Gamuts, Explained Through the Story of 1655 Orange
    • #pre-press preparation #bleed #resolution #color mode #fonts converted to outlines

    FAQ

    Can the printer add bleed if it wasn't set?

    Yes, but the effect is poor. The bleed added by the printer will be white or background color, not the design's pattern. It is most accurate for the client to set bleed themselves.

    Can the printer fix insufficient resolution?

    No. Printing at insufficient resolution will result in blurry output. The client must provide high-resolution originals (e.g. 300dpi).

    Can the printer print RGB files directly?

    Yes, the printer will automatically convert to CMYK. But the conversion will cause color shift (10–20%). It is recommended that the client convert to CMYK themselves and confirm the color before sending to the printer.

    Can the printer open the file if fonts aren't converted?

    Yes, but the fonts will become the system default font (e.g. SimSun). If the client used commercial fonts, the printer's computer may not have them installed. It is strongly recommended that the client convert to outlines.

    Should I use CDR, AI, or PDF?

    AI (Illustrator) and PDF are recommended. CDR has poor compatibility on newer Mac/Win; CDR files should be converted to PDF before sending.

    📚 📚 Related Recommendations

    Digital printing Digital Printing of Shrink Film Labels: 3 Practical Boundaries — Shrink Rate / Sample Distortion / Material Matching: When a Client Compares Color Against a Real Bottle Photo, What 3 Figures Should the Printer Ask for First? 3 min Digital printing Digital Printing "All-in-One Machines": 3 Real Boundaries—Changeover Time / Precision Loss / Capacity Bottlenecks—The First 3 Questions Printers Should Ask When Customers Say "Can You Do It in One Pass" 3 min Digital printing Digital Proofing vs Production Press: 3 Real Differences and How to Handle Color Shifts After Approval 3 min Digital printing Four Real-World Boundaries of Digital Inkjet Inks: Solvent / Semi-Solvent / Water-Based / UV-Curable — What Printers Should Ask First for Water- and Sun-Resistant Orders 3 min

    Need a Custom Packaging Solution?

    Learn more about packaging, or consult directly for a custom solution and quote

    📋 Get Quote 💬 Online Chat