Understand colour shifts from screen to paper

The PDF looks bright on screen, then the printed sheet comes back duller, darker, or shifted. A vivid blue leans purple. A fresh orange turns brown. A pale grey background becomes visible banding. It is tempting to treat this as a broken PDF, but the deeper cause is that the screen and the sheet are making colour in physically different ways.

A monitor emits light. Paper reflects light. Ink absorbs part of that reflected light. Moving a design from screen to print is therefore not a simple copy; it is a translation between colour systems with different limits. Some colours you can see on a screen cannot be produced by ordinary inks on ordinary paper.

RGB and CMYK do not share the same gamut

RGB is additive. Red, green, and blue light are combined to make the colour you see on a display. Add enough of all three and the result moves towards white. That makes screens especially good at bright, saturated colours, because the light is coming directly at you.

CMYK is subtractive. Cyan, magenta, yellow, and black inks sit on paper and absorb parts of the light falling on them. The colour you see is what remains after absorption and reflection. Add more ink and the result moves darker, not brighter. Paper whiteness, ink density, and drying behaviour all become part of the colour.

The two gamuts overlap, but not completely. Very vivid blues, greens, and oranges often have no direct ink equivalent. A print workflow has to choose the closest printable colour, and “closest” depends on the profile and rendering intent being used. That is why a home inkjet will not exactly match a calibrated press, and neither will perfectly match a glowing screen.

What colour profiles do

A colour profile describes how a device or working space represents colour. Your screen has a profile. A press condition has a profile. A PDF can contain tagged images and objects with their own profiles. Without profiles, numbers are ambiguous: RGB 0, 80, 255 is just a set of values until a colour space says what those values mean.

“Convert to destination” means translate colours from their current source spaces into the destination profile requested for output. In print work, that destination is often a CMYK profile supplied by the print shop. The conversion does not magically preserve impossible colours. It chooses print-safe values for that output condition so the result is predictable rather than accidental.

Ask the print shop which profile they want, and use that. If they request a specific CMYK profile, send a PDF prepared for that profile rather than guessing. If they ask for RGB because their own pipeline handles conversion, follow that instruction instead. The important part is not choosing CMYK in the abstract; it is matching the actual output process.

Black text is not the same as rich black

Body text should usually be true black: 100% K, with no cyan, magenta, or yellow. That keeps small letters sharp because only the black plate has to align. If body copy is built as a four-colour rich black, tiny registration differences can make text look fuzzy or coloured at the edges.

Rich black has a place in large solid areas where plain 100% K may look flat. Designers often mix black with other inks to create a deeper panel or background. Use it deliberately for large shapes, not by accident for eight-point legal text, QR codes, or fine rules.

Spot colours add another layer. A spot colour is intended as a separate named ink or a managed substitute. If the job will be printed digitally without that ink, the spot may be converted to process colours and shift. Confirm with the printer before relying on a brand colour or special ink effect.

Transparency flattening can change appearance

PDFs can contain transparency, blend modes, shadows, and overlapping objects. Some print paths support modern transparency directly. Others flatten it into simpler objects before output. Flattening can split artwork into tiles, rasterise parts of the page, or change how a blend interacts with a colour conversion.

The visible symptom is often local: a shadow box darkens, a transparent overlay turns muddy, or a boundary appears where none existed on screen. If your design uses transparent effects over photographs or gradients, proof the actual PDF that will be printed, not a screenshot of the layout.

Exporting page images with the PDF to JPG tool can be useful for screen review, but it is not a substitute for a print proof. A JPG preview is still an RGB image unless the print workflow says otherwise.

Paper and ink are part of the colour system

Glossy coated paper holds ink differently from uncoated office paper. Newsprint, recycled stock, and absorbent card can make colours look softer and darker. Ink spreads into fibres, highlights lose brightness, and fine reversed text can fill in. The same PDF can therefore produce noticeably different results on two paper stocks.

Home printers add their own limits: small ink sets, driver-managed colour, consumer paper profiles, and automatic enhancement settings. They are useful for layout checks, but they are not contract proofs. A calibrated press with the right profile and paper proof is a different standard.

Monitor calibration matters too. If your display is too bright or too blue, every print will look dull or warm by comparison. Soft proofing can help, but it is only as good as the monitor profile, viewing light, and destination profile.

Practical steps before you print

Send the print shop the profile they ask for, or ask before exporting if the job matters. Proof a single page first, especially one with photographs, brand colours, black text, transparency, and large solids. Keep body text as true black unless the printer gives a reason not to.

Avoid extra processing after a print-ready export. Heavy image recompression can introduce banding or artefacts in gradients and photographs. If you do need to reduce file size for delivery, use the compress PDF tool carefully and inspect image-heavy pages afterwards. If the trim or artwork size is wrong, correct page geometry with the crop and resize PDF tool before proofing, because scaling and cropping after approval can alter how the piece is produced.

A short checklist

• Accept that some RGB colours have no CMYK ink equivalent.
• Use the destination profile requested by the printer, not a generic guess.
• Keep small body text and fine rules as true 100% K black.
• Ask how spot colours will be handled before relying on them.
• Proof one representative page on the intended paper or with the intended print provider before approving the full run.
• Treat home inkjet output as a rough check, not a match for a calibrated press.