Prepress Basics
Prepress checks a document against the intended printing and finishing conditions. No single colour mode, resolution or page-box setting proves production suitability by itself.
Prepress checks a document against the intended printing and finishing conditions. No single colour mode, resolution or page-box setting proves production suitability by itself.
Colour and resolution
RGB describes light-based colour; CMYK describes process-ink channels. An RGB object is not automatically a defect: the PDF/X target, ICC information and provider's RIP/DFE workflow matter. NowToPrint preserves colour content instead of silently forcing it into CMYK. See colour management.
PPI describes raster pixels per inch at the placed size. DPI describes output-device dots per inch. They are not interchangeable. A 1200-pixel image placed 4 inches wide has 300 PPI; placing it 8 inches wide gives 150 PPI. Ask the provider for the target for the viewing distance and process. Changing a resolution label does not recover missing detail.
Page boxes and artwork
| Term | Meaning |
|---|---|
| MediaBox | PDF page's outer media boundary |
| CropBox | Region used for display/clipping where applicable |
| TrimBox | Declared intended finished boundary |
| BleedBox | Declared bleed boundary |
| ArtBox | Declared artwork extent; not an inferred trim line |
| Safe zone | Provider-agreed inner margin for important content; not a standard PDF page box |
Read whether boxes are explicitly present. A PDF default or inferred display boundary is not evidence of an authored TrimBox or BleedBox. Choosing a box does not create background artwork outside the trim. Bleed and safe margins depend on the product and finishing process; 3 mm and 5 mm are examples, not universal requirements.
Marks and production review
Crop/cut strokes, registration marks and colour bars have different colour semantics. They are not all Registration colour. Use the print-mark reference and the provider's instructions.
Start with preflight, then read what was measured, sampled or unavailable. Keep the original PDF and review proposed changes before applying them. A clean screen preview is not a press proof.
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