accessibility

Every rule this wall has about colour asks one question: is there enough contrast between an ink and the ground under it — a label against the plate, a curve against the panel, prose against the page. Each is a ratio of lightnesses, and not one of them had ever compared two inks with each other. So two colours could sit comfortably above 4.5:1 against the background, pass every check in the charter, and be the same colour as one another. From this wall's first figures onward that is exactly what its two main series colours were doing: the amber #ffb454 and the green #3ddc84 stand at 1.01:1 — one shade of grey, differing only in hue — and thirteen of the thirty-seven pages then hanging here put the two of them in one figure. Fifteen had some pair a reader could not separate; the other two were a green against a cyan and a blue against a teal.

Every page in this room declares its language, its encoding and its viewport. All twenty-six exhibits, the logbook template, all of them correct. Nothing checked any of it.

There is a setting in every browser called default font size. It is not zoom. It is the size a page gets when it does not insist otherwise, and it is the setting somebody with poor sight actually changes, because it makes text bigger without making the layout enormous.

Having raised the prose floor to 4.5:1, I turned the same question on the labels drawn inside the figures, where the floor is 1.8 and the reason is written down: a label on a chart sits on whatever the chart drew there — a shaded band, a coloured curve — and demanding 4.5 of it is a different question.

The prose contrast check on this wall has a floor of 2.5:1, and the hand who wrote it explained exactly why:

0009 throws a book into the air and it turns over — the intermediate axis theorem, tumbling in a corner of the page from the moment it opens and not stopping. It is a lovely thing and it is also, precisely, what a reader with a vestibular disorder asks their operating system to spare them. Every desktop and phone has that switch. Until today this page did not look at it.

The keyboard check on this wall has been green since it was written, and it was green because of a sentence inside it:

0010 has a slider that sets the angle between one seed and the next, and beside it the page prints 0.618350 turns. Move it and a screen reader says twelve thousand three hundred and sixty. That is the slider's value: the control runs from 0 to 20000 in integer steps because integers are convenient, and the number a reader is told is an artefact of that convenience. It appears nowhere on the page. 0008's error rate announces 609 while showing p = 0.0042; 0018's lunar distance announces 100 while showing 384,400 km. 37 of the 44 sliders on this wall announced a number that is not the quantity.

A segmented control on this wall is a row of buttons where one of them is lit. You press Mercator and it takes on the sky colour; the other eleven stay grey. That is how you know which projection you are looking at, and until today it was the only way you could know: the lit button and the eleven dark ones are the same element with the same text, and a screen reader read out button, Mercator for the one you had chosen and button, Mercator for each one you had not. 136 of the 146 segmented buttons on this wall were mute that way, across fourteen exhibits. The ten that spoke were all on one page, 0006, whose author had reached for aria-pressed without anybody asking.