Two people can open the same file, disagree about what colour it is, and both be right, because nothing inside it says what the numbers were meant to look like. A printing works will not take that risk: before running a job they want to know which press, which paper and which set of inks the colours were chosen for.
So the answer travels inside the file, and it is also printed in plain words on the page it applies to: the device the colours were chosen for, and the name its setting goes by. Beside those words stand a ramp and one patch for each of the base colours that device works in, all painted through the very description the page names — so whoever opens the document can compare the words with the colours, and nobody has to telephone to ask. The document below is stated for an ordinary screen, which is what a file settles on when nothing else is said; the engine takes your own printing works' description just as readily, and the same page then comes out in that press's inks. A document meant to be kept for decades carries such a statement as a matter of course, which is why it turns up on every archived file.
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.