Colour the document defines

The same six colours said as bare numbers and then read through the sRGB profile the file carries, plus a ramp from light to dark and a sweep of hues in CIE L*a*b*: colour that still means the same thing on another screen and on a press.

Three numbers written into a file say only three numbers: what they look like is left to whatever shows them. The rows on this page say colour two other ways: through the ICC profile the file carries, so the numbers mean what they meant when the document was made, and as CIE 1976 L*a*b*.

L*a*b* is worth a look even if you never use it, because lightness and colour are two separate numbers in it: the ramp on this page changes one number, and the sweep of hues changes the other two. This is what a document does when the colour on the page has to survive the journey to somebody else's screen or press.

What this example shows

  • Bare numbers set beside the same numbers read through a profile.
  • An sRGB profile carried inside the document itself.
  • A ramp from light to dark and a sweep of hues in CIE L*a*b*.

The code, in full

The same document is written twice, once in each language. Both files are shown in full, with the code coloured on the server, and can be copied in one click.

The document itself

The same document is written in each of these languages. Open the one you want to look at.

Open the document in English Open the document in French

Read the Rust source Read the Python source

First page of Colour the document defines

What this document weighs

Before 113,403 bytes
Now 42,897 bytes
Saved 62.2 %

Not one mark on the page changed. See every document measured.

Examples near this one

Grey, screen and printing colours

Swatches in each of the three ways to say a colour — a grey as one number, a screen colour as three, a printing colour as four inks — each captioned with the instruction actually written into the file, and one mid-grey said three ways.

Inks on plates of their own

Two inks the press carries on a plate of their own, each at ten strengths, a piece of work set in both, and the crosses used to line the plates up — drawn in an ink every plate answers to.

Several plates at once, each at a strength of its own

Eight choices of plate among the four usual inks, each with the small program that shows it printed underneath, and two inks the press carries itself used together, every strength of one against every strength of the other.

A chart of colours, and a drawing that names places in it

A chart of house colours the file carries, and a drawing whose sixteen numbers are places in that chart rather than colours. The same drawing is shown twice through two charts: repainting a whole brand is one table, not every drawing.

One hatch, laid down in as many colours as the page asks for

One pattern that states no colour of its own, laid down in five colours and in five strengths of one press ink: the fill says what colour to lay it down in. Beside them, the same hatch made of patterns that carry their own colours, which is one pattern per colour.

A sheet as it goes to the press

One drawing on three pages: a press sheet stating where the ink runs, where the blade falls and what is worth keeping, with corner marks; the same sheet cropped to the finished page; and a landscape page that states a quarter turn clockwise on an upright sheet.

Every example, by subject

Glossary

colour profile
A file that says what a colour actually looks like. Without one, the same red is one red on your screen and another on a press. A document meant for print carries the profile its colours were chosen against.