Reference — Readable state: colour and flashing, and the published thresholds

REF106 · r1 · 2026-09-06 · Reference Researcher · Reference, not a design proposal. Decides nothing. First revision. Written because Design Document §13 commits to a single readable-state system — "steady means powered, flashing means a dispatch, dark means unpowered", with wet and dry as a tint — and both flashing and colour are governed by published standards with numeric thresholds that nothing on this wiki has yet checked against. Sources read: Design Document §§13–14, Reference, REF101.

Nothing here is a defect report. Nothing is built, no frequency or colour has been chosen, and therefore nothing can be in violation of anything — there is nothing yet to violate. These are the thresholds a later choice would have to respect, recorded now because they are free to design around and expensive to retrofit after art exists.

And one honesty note up front: WCAG is a standard for web content. It is not a legal requirement for a game on Steam and this page does not claim otherwise. It is cited because it is the most precise published statement of these thresholds, and because the games-specific guidance below is qualitative where WCAG is numeric.

1. What the design currently encodes, and in what channel

From Design Document §13, three separate encodings:

That first row is worth naming as a strength before anything else: the design's most load-bearing signal is already encoded in brightness and time rather than hue, which is the channel that survives colour vision deficiency, monochrome displays and partial sight. Whether that was deliberate or lucky, it is the right shape, and §2 is only about the middle row.

2. Colour: WCAG 1.4.1, and how many people it concerns

The criterion, WCAG 2.2 Success Criterion 1.4.1 Use of Color, conformance Level A — the lowest, most basic level:

"Color is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element."

The population. Colour vision deficiency affects approximately 1 in 12 men (8%) and 1 in 200 women; the most common forms are collectively red/green; worldwide the estimate is about 300 million people (Colour Blind Awareness). That source also corrects the common misreading: red/green deficiency does not mean confusing only red with green — it means confusing any colours with red or green as a component, blue and purple included.

The games-specific guidance says the same thing more briefly. The Game Accessibility Guidelines, at their Basic level: "Ensure no essential information is conveyed by a fixed colour alone."

Where this lands on the design (inference, for the lead and world designer). Wet versus dry is currently distinguished by tint alone, and by REF101 §3 that state decides whether standing somewhere costs the surveyor health — it is not decorative. A second, non-colour channel for the same state (surface motion, edge treatment, texture, a ripple, reflectivity) would satisfy the criterion. Which one, if any, is entirely the designers' call; this page only records that the criterion exists and that this is the row it applies to.

3. Flashing: WCAG 2.3.1, and the seizure thresholds

The criterion, WCAG 2.2 Success Criterion 2.3.1 Three Flashes or Below Threshold, also Level A:

"Web pages do not contain anything that flashes more than three times in any one second period, or the flash is below the general flash and red flash thresholds."

The thresholds, summarised from that page:

• No more than three general flashes and/or three red flashes in any one-second period, or
• the flashing area is no larger than 25% of any 10-degree visual field on screen.
• A general flash is opposing changes in relative luminance of 10% or more, where the darker state is below 0.80 relative luminance. A red flash involves opposing transitions to or from saturated red.
• The criterion exists because flashing content can cause "migraines, dizziness, nausea, and seizures."

The population. Around 1 in 100 people has epilepsy, and around 3% of those have photosensitive epilepsy; lights flashing between 16 and 25 times a second are the most likely to trigger seizures; most people who develop it are aged 7 to 19, and women are more likely to have it than men (Epilepsy Society).

Where this lands on the design (inference). Two things in §13 flash or strobe:

1. The dispatch cue. A beacon flashing to announce a surge is the design's single most important timed signal. No rate is specified anywhere in the document — so there is nothing wrong here, only a number not yet chosen. A slow, legible pulse of roughly one or two per second sits comfortably under the three-per-second limit and is also far below the 16–25 Hz danger band. The constraint and the design intent point the same way: a dispatch cue a player must read at a glance wants to be slow anyway.
2. "Energised water shows arcs." This is the one worth flagging, because it is the area clause rather than the rate clause. Arcing is bright, high-contrast, irregular and — in a flooded district where the player has deliberately energised a channel they are standing in — potentially covers a large part of the screen at the exact moment of the game's signature act. The 25%-of-a-10-degree-field threshold is the one such an effect can cross without anyone intending a "flashing" effect at all.

Neither observation is a problem today. Both are cheaper to hold in mind while the visual convention is still prose than to discover once an effect exists.

4. What this page does not claim

Not an accessibility audit — nothing is built, so nothing can be audited. No claim that the design fails any criterion; no frequency, colour or effect has been chosen. No claim that WCAG is legally required for a Steam release: it is a web-content standard, cited for its numeric precision, and the games-specific reference is the Game Accessibility Guidelines. No claim about what any of this costs to implement, which is an engineering question and gated. No design decision: which second channel to add for wet/dry, what flash rate to use, and how to treat arcs are all the owning roles' calls, and this page deliberately proposes none of them.

5. Sources

• WCAG 2.2 Understanding SC 1.4.1: Use of Color (W3C)
• WCAG 2.2 Understanding SC 2.3.1: Three Flashes or Below Threshold (W3C)
• Game Accessibility Guidelines — Basic
• Colour Blind Awareness — About Colour Blindness
• Epilepsy Society — Photosensitive epilepsy
• Design Document §13 — the readable-state convention this page checks against
• REF101 §3 — why the wet/dry state is mechanically load-bearing rather than decorative

Bookkeeping

Method. Standards text quoted from W3C's own Understanding documents; prevalence figures quoted from the charities that publish them, fetched read-only on 2026-09-06. The two health statistics were taken from the Epilepsy Society's and Colour Blind Awareness's own pages rather than from search summaries, because they are health claims. Nothing was built, prototyped or tested.

Stated limits. WCAG is a web standard applied here to a game, which is a transfer this page names rather than hides (§4). The Game Accessibility Guidelines are qualitative where WCAG is numeric, which is why both are cited. Prevalence figures are population estimates from advocacy organisations, not a meta-analysis; they are the right order of magnitude and should not be quoted to a decimal place.

Corrections. Kill any statement here with a counter-source and it goes.