Carrying a colour profile inside a document costs a few hundred kilobytes, on every copy, and there are documents that cannot afford it: a statement sent to a million people, a form pulled down over a poor connection. It looks like a choice between colour that means something and a file that stays small, and it is not one.
You are looking at one row of colours and one grey ramp, each painted three times over with the very same numbers. The first time the numbers are handed over as they are: the shortest thing to write, and every screen and every printer then settles for itself what they look like. The second time they are said against a stated white and a stated set of base colours, which pins down what they mean, whoever opens the document. The third time the base colours are a wider set, and the same numbers reach deeper, more vivid tones. The greys follow the same three steps, once spread out evenly by measurement and once spread out evenly to the eye — which is why the two ramps do not look alike even though the ten numbers behind them are identical. All of it travels in a handful of numbers, and there is no profile to carry.
Nothing is left out and nothing is simplified: this is the program exactly as it runs, for the developer who uses this library. The third is the description itself: a plain list of what the page has to say, which is what the service is sent.
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The document is lighter than it was, and every page still looks exactly the same. See this document's row in the table of every example.
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.
The same six colours said as bare numbers and then read through the screen profile the file carries, plus a ramp from light to dark and a sweep of measured hues: colour that still means the same thing on another screen and on a press.
Two inks the press carries on a plate of their own, each at ten strengths, a piece of work set in both, and the alignment crosses used to line the plates up — drawn in an ink every plate answers to.
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 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 chart, not every drawing.
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.