How four inks make every colour on the page, what paper and press do to it, and what a printer needs from you.
Also: process colour, four-colour process, full colour
The four inks a press makes every colour from: cyan, magenta, yellow and black (K, for the key plate). Each ink is printed from its own plate as a halftone of tiny dots, and the four layers mix on the paper.
Each plate prints one ink. Cyan carries the sea and sky, yellow the sun and half of every green, black the mast and the deepest shadows.
Also: colour gamut, out of gamut
The range of colours a screen can show or a press can print. A screen’s light reaches brighter greens, blues and oranges than four inks can, so those colours print duller than they look.
The brightest screen colours are outside what four inks can reach, so they print duller. Quieter colours print as they look. (A screen can only imitate ink: trust a printed proof.)
Also: Pantone, PMS colour, special colour
An ink mixed to an exact colour before printing, instead of being built from CMYK dots. Spot colours are chosen by number from a matching system, most often Pantone, and some reach colours CMYK can’t, such as metallics and fluorescents.
A spot colour is one ink, mixed to a recipe before printing. Under a loupe it is solid colour.
Also: screen, screen tint, percentage tint
A lighter shade of one ink, printed as smaller dots so more paper shows between them. A 20% tint of a blue costs nothing extra: it is the same ink on the same plate.
The causeway to the island floods twice a day. Check the tide times at the harbour before you walk out.
A tint is the same ink as smaller dots, so more paper shows. Behind text, keep it light, or the words sink into it.
Printing with only two inks, usually black and one spot colour, using tints of each for panels and shading. Fewer plates usually means a lower price on an offset press, so pocket guides and workbooks often print this way.
Black and one blue do everything in this pocket guide: the heading in solid blue, the box in a tint of it, the photo as a duotone of both.
Also: in register, out of register, misregistration
How exactly the plates line up as they print on the same sheet. In register, every dot lands where it should; out of register, the colours slip apart and edges grow coloured fringes.
When the plates slip, the target splits into its colours and every edge in the picture grows a fringe.
Also: four-colour black
Black ink with some cyan, magenta and yellow printed under it, so a large area looks deep instead of dark grey. Recipes vary by printer; 60 cyan, 40 magenta, 40 yellow and 100 black is one common example.
The big panel is deep and even. But the small text is on four plates now, and their slight misfit blurs it with colour.
Where one colour sits on another, the ink underneath can stop where the top one starts (knockout, the usual way) or carry on under it (overprint). Black is normally set to overprint, so black text never shows a white edge.
The yellow has holes where the circle and word go. When the plates slip, paper shows through at one edge.
Also: tone value increase, TVI
Printed dots come out larger than in the file, because ink spreads as it meets paper. The mid-tones darken most, uncoated paper gains more than coated, and the printer’s colour profile allows for it.
Ink spreads as it meets paper, so every dot prints a little fatter. Highlights and solids hardly move; the mid-tones darken most. Drawn larger than life.
Also: ICC profile, output profile
A file describing how one kind of press and paper reproduces colour, so software can turn your colours into the CMYK numbers that print right there. In Europe, PSO Coated v3 (FOGRA51) and PSO Uncoated v3 (FOGRA52) are common; older jobs use ISO Coated v2 (FOGRA39).
Start at the cathedral and walk downhill towards the river. The tram stop is on your left.
Converted with the uncoated profile, the picture is prepared for how this paper takes ink, and prints as close to the screen as it can.
Also: total area coverage, TAC, ink limit
The four inks’ percentages added up at the darkest point of a page. Each can be 0 to 100%, so the most is 400%, but too much ink won’t dry in time, so every printer sets a limit for each paper.
A rich black of 60, 40, 40 and 100 adds up to 240%: deep, and still under a typical limit.
Also: cover finishes, print finishing
Treatments added to a cover after it is printed. Lamination is a thin plastic film over the whole cover, matt or gloss, that protects it; spot UV is a clear gloss varnish on chosen areas; foil is a metallic film pressed on with heat.
Spot UV: clear gloss varnish on the title and the pattern, which is printed in the same navy as the cover. Against matt, they catch the light.