Fix the final size and composition first
Print preparation guide
A Practical Print File Preflight Checklist
Check trim, crop, effective PPI, bleed, safe area, color, file format and proofing in the right order before sending artwork to print.
Quick answer
A useful preflight is more than a 300 PPI check. Confirm the finished trim and orientation, position the final crop, calculate effective PPI from the pixels that remain, add the provider's bleed and safe margin, then verify color, file format, fonts and proofing instructions.
specification → crop → effective PPI → bleed → export → proofCalculate from usable post-crop pixels
Bleed, color and export rules are product specific
Decision table
What to verify at each preflight stage
| Stage | Question | Evidence | Common failure |
|---|---|---|---|
| Product | What exact item is being printed? | Written provider specification | Using a generic size or bleed |
| Composition | Will the image fill or fit? | Final crop preview | Faces or text cut at the edge |
| Resolution | How many pixels remain per inch? | Horizontal and vertical effective PPI | Trusting a metadata tag |
| Document | Where are trim, bleed and safe area? | Visible document boxes | Adding bleed to only one edge |
| Export | Does the file match the workflow? | Provider format and color instructions | Guessing PDF, JPEG or CMYK settings |
Start with the product specification, not the artwork
Write down the finished trim size, orientation, bleed on each edge, safe margin, preferred file format, color profile and minimum or recommended image PPI. A business card, photo print, paperback cover and trade-show panel can all use different rules even when their physical dimensions appear similar.
If the provider offers a template, use that template as the geometry authority. Generic defaults such as 3 mm bleed or 300 PPI are useful examples, but they do not override the instructions for the product you are buying.
Lock trim, orientation and crop before judging resolution
Trim is the finished cut size. Decide portrait or landscape, then choose whether the image will fill the page, fit inside it with borders, or sit within a designed layout. A ratio mismatch changes the crop and therefore changes the number of usable pixels.
For example, a 6000 × 4000 px 3:2 image filling a 16 × 20 inch 4:5 frame retains about 5000 × 4000 px. The final density is therefore 250 PPI in both directions, not the 300 PPI someone might infer by dividing the original 6000-pixel edge by 20 inches.
Calculate effective PPI from the final usable pixels
Divide the post-crop pixel width by the printed width in inches and repeat for height. Use the lower result as the limiting effective PPI. This calculation answers whether the raster contains enough source pixels for the selected target.
Do not substitute file size in megabytes or the 72/300 value stored in metadata. Compression, layers and format change megabytes; a metadata tag changes suggested scale. Neither creates captured detail. Inspect focus and compression separately because a numerically dense but blurred image can still print poorly.
Build bleed and protect the safe area
Extend edge-to-edge backgrounds beyond the trim by the provider's bleed value. Bleed is added to both sides of each dimension: an A4 trim at 210 × 297 mm with 3 mm bleed becomes a 216 × 303 mm canvas. It does not make the finished piece larger.
Keep text, logos, faces and other critical details inside the safe margin. The safe area is not a guarantee against every finishing variation; it is a deliberate buffer inside the trim. Fold lines, binding, perforation and rounded corners may need additional product-specific protection.
Verify export, color and proofing without guessing
Follow the provider's requested file type, color profile, transparency, font and compression settings. Converting every file to CMYK or flattening every PDF is not automatically correct; some services request sRGB JPEG files while others supply a specific PDF and CMYK workflow.
Open the exported file again, check its final dimensions and page count, zoom into edges and small text, and confirm that no crop or bleed guides were accidentally exported as artwork. For important jobs, order a physical proof or the provider's closest equivalent before committing to the full run.
Use a repeatable twelve-point sign-off
Before delivery, confirm: product, trim, orientation, crop, usable pixels, effective PPI, bleed, safe area, color instructions, file format, embedded or outlined fonts where required, and proof approval. Record the provider specification beside the exported file so a later revision uses the same assumptions.
A checklist cannot remove every production variable, but it prevents the most common category error: solving the right calculation for the wrong final product.
Practical workflow
Use this order before you export.
- Save the provider's specification and template for the exact product.
- Fix trim, orientation and the final fill-or-fit crop.
- Calculate effective PPI from the post-crop pixels.
- Add bleed, protect the safe area, export to specification and inspect the exported file.
Sources and method
Check the requirement behind the number.
These guides explain repeatable calculations and planning ranges. The print provider's written specification remains the final production requirement.
Put the guide into practice
Run the print readiness check →Lock the product specification first, then verify geometry, pixels and production settings in that order.
Use the linked calculator with your own dimensions, then verify the result against the provider's production requirement.