Print and Colour Management

Why a print does not match the screen, what happens to a bright blue in CMYK, why a black prints brown, and when a spot colour is worth it. Professional colour-management concepts explained without the jargon wall.

Explains commercial print concepts and published characterisation data. No proprietary spot-colour library is reproduced.

14 topics · 52 evidence-labelled claims · 20 sources

Tools

Print gamut check

Screen to print

RGB to CMYK, gamut and rendering intents.

Why doesn't my print match what I see on screen?A screen makes colour by emitting light; a print makes it by subtracting light from paper, so the two have different gamuts, a di…How is RGB converted to CMYK, and why is there no single right answer?RGB is converted to CMYK through colour profiles: the RGB values are turned into device-independent colour (CIELAB or XYZ) using…Why do bright blues and purples go dull when printed in CMYK?Because a printed blue is made by overprinting cyan and magenta, and both inks absorb more of the blue light they are meant to pa…What are rendering intents, and which one should I use for print?A rendering intent is the rule a colour-managed conversion follows for colours and tones the destination cannot reproduce.

Inks, paper and press

Black generation, ink limits, dot gain and paper white.

What is rich black, and why does my black print brown or grey?Black ink alone (100 % K) is not very dark: on coated offset it reaches about L* 16, on uncoated about 33.What is total ink coverage, and what limit should I use?Total ink coverage (the tone value sum, or TAC) is the sum of the four ink percentages at the darkest point of a file — at most 4…What are GCR and UCR, and how does black generation change a print?Black generation is how a separation decides how much black ink to use in place of equal-looking amounts of cyan, magenta and yel…Why does paper white matter, and what are optical brighteners and M1?Every printed colour sits on the paper, so the paper's own colour shifts all of them and sets the lightest white.Why do colours look so different on coated and uncoated paper?On coated paper the ink film stays on a smooth, closed surface, so solids are dense and saturated and dots stay sharp.What is dot gain (tone value increase), and why do prints come out darker?Tone value increase (TVI), the modern name for dot gain, is how much darker a halftone tint prints than the percentage in the fil…

Profiles and proofing

ICC profiles, soft proofing and tolerances.

Which ICC profile should I use for print, and where do they come from?Use the profile for the printing condition your job will actually be printed to — ideally named by the printer — because each sta…What is soft proofing, and how far can I trust it?Soft proofing is previewing on a monitor how a file will look when printed to a specific condition: the software converts the col…How close does a contract proof have to be, and what tolerances apply?Under ISO 12647-7:2016 a contract proof is checked by measuring a control strip and comparing it with the characterisation data o…When should I use a spot colour instead of CMYK process colour?Process colour builds every colour from dots of cyan, magenta, yellow and black; a spot colour is a separate ink mixed to one tar…