Tiny Online Tools
Why total area coverage is the number that matters
A press has a ceiling on how much ink it can lay down before the sheet stops drying, offsets onto the next one, or simply refuses to hold detail. That ceiling is expressed as total area coverage — the sum of the four plates at a point. 240% is normal for coldset newsprint, 280–300% for uncoated and coated offset, 320% for good coated sheetfed. A rich black of C60 M40 Y40 K100 is 240% and prints beautifully. The same black with C95 M90 Y85 K80 is 350% and will come back from the printer as a question.
This tool finds those areas before the printer does.
What it reports
- Mean coverage of each plate, per page and for the document.
- Total area coverage per page, the maximum TAC found anywhere on the page, and the fraction of the page that sits over your chosen limit.
- A heat map over the page image showing where the heaviest coverage is, with an opacity control.
- Which pages are visually greyscale — a page that declares CMYK but is visually grey can be printed on one plate, which is a real cost difference.
- A rough ink-consumption estimate, at about 1.2 grams per square metre per 100% of one ink.
Two readings, and why they differ
The rendered estimate rasterises each page and converts the pixels back to CMYK. That conversion is not colour-managed: there is no ICC profile, no black generation and no undercolour removal, and the renderer has already collapsed whatever the file declared down to RGB. A 350% rich black renders as near-black and converts back to roughly 100%. The estimate is useful for photographs and flat art; it systematically understates heavy blacks.
So the tool also reads the k and K operators straight out of the content stream and reports the TAC the file declares. That figure is exact for everything painted in DeviceCMYK. Where the two disagree, believe the declared one.
Neither is a substitute for the RIP's own preflight, which knows your press profile. Treat this as the check you run before you send the job, not the one your printer runs after.
Privacy
Everything runs in your browser. The PDF is never uploaded.