Preflight Check

Preflight is the final quality gate before a PDF enters production — much like the pre-flight checklist a pilot completes before takeoff. Catching errors here costs a fraction of what they cost after printing.

The 1-10-100 Rule

Stage	Cost	Action
Catch error at design stage	$1	Fix on screen
Catch error at preflight	$10	Return file to customer
Catch error after printing	$100	Wasted paper, ink and time

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What Gets Checked

1. Image Resolution (DPI)

• Web standard: 72 DPI — too low for print, will appear blurry
• Print standard: 300 DPI minimum
• Files below 200 DPI trigger a Low Resolution error

2. Bleed and Safe Zone

• Bleed: Background must extend 3 mm beyond the trim line so there are no white edges after cutting
• Safe zone: Keep all important text and logos at least 5 mm from the trim line

3. Font Embedding

All fonts must be embedded in the PDF. If a font is not embedded the print shop's system may substitute a different typeface.

4. Colour Mode

• RGB — for screens (Red, Green, Blue light)
• CMYK — for print (Cyan, Magenta, Yellow, Black ink)

RGB files are accepted but colours may shift during conversion, especially bright oranges and neons.

5. Document Size

Does the file size match the product ordered? An A4 PDF submitted for an A5 order is a blocking error.

6. Page Count

Booklets and books must have a page count divisible by 4 (required for folding and binding).

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Traffic Light System

NowToPrint checks files against ISO 12647 and assigns one of three results:

Result	Colour	Meaning	Action
Pass	Green	File is perfect	Send to print
Warning	Yellow	Minor risk (e.g. 220 DPI image)	Can print with your approval
Error	Red	Critical issue (e.g. missing bleed)	Must fix before printing

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PDF/X Standards

The system automatically converts files to the appropriate PDF/X standard:

• PDF/X-1a: Safest, widest compatibility. Flattens transparency. Minimises risk.
• PDF/X-4: For modern RIPs. Preserves transparency and layers, richer colours.

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Knowledge Check

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Common Errors and Fixes

"Low Resolution Images Detected"

Problem: Images below 200 DPI.
Fix: Source the original high-resolution image, replace in design, or reduce the element size.

"Missing Bleed"

Problem: Background does not extend beyond the trim line.
Fix: In InDesign/Illustrator set Document Bleed to 3 mm, extend background, re-export.

"Fonts Not Embedded"

Problem: Custom fonts not embedded in PDF.
Fix: In export settings enable "Embed All Fonts", or outline the text before exporting.

"RGB Colour Space Detected"

Problem: Images or colours in RGB mode.
Fix: In Photoshop: Image → Mode → CMYK. Check for colour shift, re-export.

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