{"course":{"slug":"vector-and-print","title":"Vectors, Logos and Things That Get Printed","url":"https://addaly.com/learn/vector-and-print","level":"beginner","track":"create"},"lesson":{"slug":"reading-separations","title":"Reading separations, and the fifth plate you did not order","url":"https://addaly.com/learn/vector-and-print/reading-separations","position":60,"of":73,"minutes":8,"answer":"Separations answer questions a composite cannot: whether your black text is really 100% K, whether a spot survived as a spot, whether there is an unordered fifth plate.","keyIdea":"Separations answer questions a composite cannot: whether your black text is really 100% K, whether a spot survived as a spot, whether there is an unordered fifth plate, and whether total ink exceeds what the press can dry."},"body":{"format":"markdown","text":"## What separations show you\n\nA composite view shows the four inks combined and looks like the finished job. **Separations** show one ink at a time, and they reveal things a composite hides entirely.\n\nFour questions that only separations answer:\n\n1. Is my black text actually 100% K, or is it four colours?\n2. Is my spot colour still a spot, or did it convert?\n3. Are there plates I did not ask for?\n4. Is anything set to overprint that should not be?\n\n## Looking at them\n\n**Acrobat Pro**: Print Production ▸ Output Preview. Tick and untick each separation, hover to read ink percentages under the cursor, and set *Total Area Coverage* to a number (300%, say) to highlight every area over the limit in a warning colour.\n\n**Free, with Ghostscript**:\n\n```bash\ngs -o sep-%02d.tif -sDEVICE=tiffsep -r300 job.pdf\n```\n\nYou get `sep-01.Cyan.tif`, `sep-01.Magenta.tif` and so on, plus a file for every spot colour, named after the spot. Open them in GIMP or any viewer.\n\nThe file list alone answers question 3 before you look at a single image. Two plates expected, five files produced: something converted.\n\n**Free, for ink coverage**:\n\n```bash\ngs -q -o /dev/null -sDEVICE=inkcov job.pdf\n```\n\nPrints four numbers per page as fractions of full coverage. Useful as a quick screen across a long document.\n\n## The black-text check\n\nOpen the Cyan separation and look at your body text. If you can read it, your black is not 100% K.\n\nThis happens in three ways, all common:\n\n- **Text drawn in RGB black** (`#000000`) converted with a standard profile, which becomes a rich black of roughly 90/70/70/100 rather than 0/0/0/100.\n- **Text copied from another document** carrying its own colour definition.\n- **A logo whose black was defined as rich black**, then reused at 8 mm on a form.\n\nThe consequence, from the colour module: four plates never register perfectly, so small text built from four inks gets a coloured fringe. Fix it in the source by setting the text to a 100% K swatch, not by adjusting the export.\n\n## Total area coverage\n\nAdd the four percentages at any point. Presses cap the total, typically:\n\n- Coated sheetfed: **300 to 330%**\n- Uncoated: **260 to 300%**\n- Newsprint and web: **240%**\n\nAbove the limit, ink does not dry, sheets offset onto each other in the stack, and the press slows down or refuses.\n\n> Figure: Three ink limits, and one rich black. Bars (per cent total area coverage): Newsprint and web limit 240; Uncoated limit 300; Coated sheetfed limit 330; 80C 70M 70Y 100K black 320. A 60/40/40/100 rich black totals 240% and is safe anywhere. The 80/70/70/100 build shown here totals 320%: comfortable on coated sheetfed, over the limit on uncoated, and impossible on newsprint, where it will not dry and the stack offsets.\n\nWhere does too much ink come from? Usually a rich black built too heavily (60/40/40/100 is 240%, which is fine; 80/70/70/100 is 320%, which is not on uncoated), or a dark photograph converted with a profile whose ink limit is higher than the press's.\n\nAcrobat's TAC warning finds it instantly. Free, the `inkcov` output gives you a page-level total, and a conversion to the correct destination profile prevents the problem rather than detecting it.\n\n## The accidental fifth plate\n\nCommon sources, in order:\n\n- An **RGB object** that nobody converted: often a logo pasted from a website, or a chart from a spreadsheet.\n- A **spot swatch** used once, on a hidden or off-page object.\n- A **Registration** swatch used as a black. Registration prints on every plate and is for crop marks only; a headline in registration black prints 400% ink and will not dry.\n- A **duplicate spot** with a slightly different name: `PANTONE 2925 C` and `Pantone 2925 C` are two plates to a RIP.\n\nThe swatches panel in your layout application usually has a *Select All Unused* command. Delete them before export, and check the separations after.\n\n## Separations on a one-colour job\n\nWorth doing even when you think it cannot go wrong. A \"black only\" job that separates into four plates is quoted as four-colour, and the difference on a 5,000-sheet run is substantial. The usual culprit is a logo supplied as an RGB or CMYK file and never converted to 100% K, or a greyscale photograph that carries an RGB profile.\n\nThe fix is upstream: convert the image to greyscale, set every swatch to K-only, and check again. A two-minute check that removes three plates from a quotation pays for itself immediately, and it is the kind of thing a client notices you doing.\n\n## The habit\n\nOpen the separations on every job that matters, look at four things (black text, plate count, spot names, overprint) and close them. Two minutes, and it catches the failures that produce a reprint rather than a complaint."},"check":{"question":"A two-colour letterhead is exported and Ghostscript's `tiffsep` produces five files: Cyan, Magenta, Yellow, Black and one named after the brand spot. The visible design uses only black and the spot. Where should the designer look first?","options":[{"text":"The output intent profile, since an incorrect intent will cause the RIP to generate process plates alongside the spot ones.","correct":false,"tempting":"An output intent describes the printing condition; it does not add separations for colours nothing in the file uses."},{"text":"The trapping settings, since in-RIP trapping generates additional process separations around spot colour edges.","correct":false,"tempting":"Trapping modifies existing separations by spreading or choking; it does not create plates for inks the artwork never specified."},{"text":"The PDF/X flavour, since X-4 preserves live transparency by splitting spot colours into process equivalents.","correct":false,"tempting":"X-4 preserves spot colours. Nothing in any PDF/X flavour converts a spot into process as a side effect of transparency."},{"text":"For an RGB or process-coloured object in the file: a pasted logo, a hidden object, a registration black.","correct":true}]},"prev":{"slug":"preflight-your-own-pdf","title":"Preflighting your own PDF, free","url":"https://addaly.com/learn/vector-and-print/preflight-your-own-pdf"},"next":{"slug":"paper-and-finishing","title":"Paper, and everything done after printing","url":"https://addaly.com/learn/vector-and-print/paper-and-finishing"},"authorship":"Founder and series editor: Dr Mustafa Mun. Written by AI models to a written standard. Exam keys checked blind by a second model: 3,665 of 3,666 agreed. Academic review invited.","review":{"status":"Draft, open for academic review"},"cite":"Addaly (2026) 'Reading separations, and the fifth plate you did not order', in Vectors, Logos and Things That Get Printed. Edited by M. Mun. Addaly. Available at: https://addaly.com/learn/vector-and-print/reading-separations (Accessed: 13 October 2026).","licence":{"name":"CC BY-NC-SA 4.0","url":"https://creativecommons.org/licenses/by-nc-sa/4.0/"},"reader":{"schema":1,"title":"Reading separations, and the fifth plate you did not order","courseTitle":"Vectors, Logos and Things That Get Printed","module":{"index":7,"slug":"the-handover","title":"The handover"},"answer":null,"keyIdea":"Separations answer questions a composite cannot: whether your black text is really 100% K, whether a spot survived as a spot, whether there is an unordered fifth plate, and whether total ink exceeds what the press can dry.","hero":{"kind":"figure","figure":{"t":"figure","label":"Figure","figure":{"type":"bars","unit":"per cent total area coverage","title":"Three ink limits, and one rich black","series":[{"label":"Newsprint and web limit","value":240},{"label":"Uncoated limit","value":300},{"label":"Coated sheetfed limit","value":330},{"label":"80C 70M 70Y 100K black","value":320,"highlight":true}],"caption":"A 60/40/40/100 rich black totals 240% and is safe anywhere. The 80/70/70/100 build shown here totals 320%: comfortable on coated sheetfed, over the limit on uncoated, and impossible on newsprint, where it will not dry and the stack offsets."},"alt":"Figure: Three ink limits, and one rich black. Bars (per cent total area coverage): Newsprint and web limit 240; Uncoated limit 300; Coated sheetfed limit 330; 80C 70M 70Y 100K black 320. A 60/40/40/100 rich black totals 240% and is safe anywhere. The 80/70/70/100 build shown here totals 320%: comfortable on coated sheetfed, over the limit on uncoated, and impossible on newsprint, where it will not dry and the stack offsets."}},"blocks":[{"t":"h2","id":"what-separations-show-you","runs":[{"text":"What separations show you"}]},{"t":"p","runs":[{"text":"A composite view shows the four inks combined and looks like the finished job. "},{"text":"Separations","b":true},{"text":" show one ink at a time, and they reveal things a composite hides entirely."}]},{"t":"p","runs":[{"text":"Four questions that only separations answer:"}]},{"t":"ol","start":1,"items":[[{"text":"Is my black text actually 100% K, or is it four colours?"}],[{"text":"Is my spot colour still a spot, or did it convert?"}],[{"text":"Are there plates I did not ask for?"}],[{"text":"Is anything set to overprint that should not be?"}]]},{"t":"h2","id":"looking-at-them","runs":[{"text":"Looking at them"}]},{"t":"p","runs":[{"text":"Acrobat Pro","b":true},{"text":": Print Production ▸ Output Preview. Tick and untick each separation, hover to read ink percentages under the cursor, and set "},{"text":"Total Area Coverage","i":true},{"text":" to a number (300%, say) to highlight every area over the limit in a warning colour."}]},{"t":"p","runs":[{"text":"Free, with Ghostscript","b":true},{"text":":"}]},{"t":"code","lang":"bash","label":"Bash","text":"gs -o sep-%02d.tif -sDEVICE=tiffsep -r300 job.pdf"},{"t":"p","runs":[{"text":"You get "},{"text":"sep-01.Cyan.tif","code":true},{"text":", "},{"text":"sep-01.Magenta.tif","code":true},{"text":" and so on, plus a file for every spot colour, named after the spot. Open them in GIMP or any viewer."}]},{"t":"p","runs":[{"text":"The file list alone answers question 3 before you look at a single image. Two plates expected, five files produced: something converted."}]},{"t":"p","runs":[{"text":"Free, for ink coverage","b":true},{"text":":"}]},{"t":"code","lang":"bash","label":"Bash","text":"gs -q -o /dev/null -sDEVICE=inkcov job.pdf"},{"t":"p","runs":[{"text":"Prints four numbers per page as fractions of full coverage. Useful as a quick screen across a long document."}]},{"t":"h2","id":"the-black-text-check","runs":[{"text":"The black-text check"}]},{"t":"p","runs":[{"text":"Open the Cyan separation and look at your body text. If you can read it, your black is not 100% K."}]},{"t":"p","runs":[{"text":"This happens in three ways, all common:"}]},{"t":"ul","items":[[{"text":"Text drawn in RGB black","b":true},{"text":" ("},{"text":"#000000","code":true},{"text":") converted with a standard profile, which becomes a rich black of roughly 90/70/70/100 rather than 0/0/0/100."}],[{"text":"Text copied from another document","b":true},{"text":" carrying its own colour definition."}],[{"text":"A logo whose black was defined as rich black","b":true},{"text":", then reused at 8 mm on a form."}]]},{"t":"p","runs":[{"text":"The consequence, from the colour module: four plates never register perfectly, so small text built from four inks gets a coloured fringe. Fix it in the source by setting the text to a 100% K swatch, not by adjusting the export."}]},{"t":"h2","id":"total-area-coverage","runs":[{"text":"Total area coverage"}]},{"t":"p","runs":[{"text":"Add the four percentages at any point. Presses cap the total, typically:"}]},{"t":"ul","items":[[{"text":"Coated sheetfed: "},{"text":"300 to 330%","b":true}],[{"text":"Uncoated: "},{"text":"260 to 300%","b":true}],[{"text":"Newsprint and web: "},{"text":"240%","b":true}]]},{"t":"p","runs":[{"text":"Above the limit, ink does not dry, sheets offset onto each other in the stack, and the press slows down or refuses."}]},{"t":"p","runs":[{"text":"Where does too much ink come from? Usually a rich black built too heavily (60/40/40/100 is 240%, which is fine; 80/70/70/100 is 320%, which is not on uncoated), or a dark photograph converted with a profile whose ink limit is higher than the press’s."}]},{"t":"p","runs":[{"text":"Acrobat’s TAC warning finds it instantly. Free, the "},{"text":"inkcov","code":true},{"text":" output gives you a page-level total, and a conversion to the correct destination profile prevents the problem rather than detecting it."}]},{"t":"h2","id":"the-accidental-fifth-plate","runs":[{"text":"The accidental fifth plate"}]},{"t":"p","runs":[{"text":"Common sources, in order:"}]},{"t":"ul","items":[[{"text":"An "},{"text":"RGB object","b":true},{"text":" that nobody converted: often a logo pasted from a website, or a chart from a spreadsheet."}],[{"text":"A "},{"text":"spot swatch","b":true},{"text":" used once, on a hidden or off-page object."}],[{"text":"A "},{"text":"Registration","b":true},{"text":" swatch used as a black. Registration prints on every plate and is for crop marks only; a headline in registration black prints 400% ink and will not dry."}],[{"text":"A "},{"text":"duplicate spot","b":true},{"text":" with a slightly different name: "},{"text":"PANTONE 2925 C","code":true},{"text":" and "},{"text":"Pantone 2925 C","code":true},{"text":" are two plates to a RIP."}]]},{"t":"p","runs":[{"text":"The swatches panel in your layout application usually has a "},{"text":"Select All Unused","i":true},{"text":" command. Delete them before export, and check the separations after."}]},{"t":"h2","id":"separations-on-a-one-colour-job","runs":[{"text":"Separations on a one-colour job"}]},{"t":"p","runs":[{"text":"Worth doing even when you think it cannot go wrong. A “black only” job that separates into four plates is quoted as four-colour, and the difference on a 5,000-sheet run is substantial. The usual culprit is a logo supplied as an RGB or CMYK file and never converted to 100% K, or a greyscale photograph that carries an RGB profile."}]},{"t":"p","runs":[{"text":"The fix is upstream: convert the image to greyscale, set every swatch to K-only, and check again. A two-minute check that removes three plates from a quotation pays for itself immediately, and it is the kind of thing a client notices you doing."}]},{"t":"h2","id":"the-habit","runs":[{"text":"The habit"}]},{"t":"p","runs":[{"text":"Open the separations on every job that matters, look at four things (black text, plate count, spot names, overprint) and close them. Two minutes, and it catches the failures that produce a reprint rather than a complaint."}]}],"check":{"question":[{"text":"A two-colour letterhead is exported and Ghostscript’s "},{"text":"tiffsep","code":true},{"text":" produces five files: Cyan, Magenta, Yellow, Black and one named after the brand spot. The visible design uses only black and the spot. Where should the designer look first?"}],"options":[{"text":[{"text":"The output intent profile, since an incorrect intent will cause the RIP to generate process plates alongside the spot ones."}],"correct":false,"tempting":[{"text":"An output intent describes the printing condition; it does not add separations for colours nothing in the file uses."}]},{"text":[{"text":"The trapping settings, since in-RIP trapping generates additional process separations around spot colour edges."}],"correct":false,"tempting":[{"text":"Trapping modifies existing separations by spreading or choking; it does not create plates for inks the artwork never specified."}]},{"text":[{"text":"The PDF/X flavour, since X-4 preserves live transparency by splitting spot colours into process equivalents."}],"correct":false,"tempting":[{"text":"X-4 preserves spot colours. Nothing in any PDF/X flavour converts a spot into process as a side effect of transparency."}]},{"text":[{"text":"For an RGB or process-coloured object in the file: a pasted logo, a hidden object, a registration black."}],"correct":true,"tempting":null}],"order":[2,3,0,1],"why":null},"prev":{"slug":"preflight-your-own-pdf","title":"Preflighting your own PDF, free","minutes":9},"next":{"slug":"paper-and-finishing","title":"Paper, and everything done after printing","minutes":8}}}