Three Flashes
Tier 1 · The normative floor
Baseline compliance
What the normative text of WCAG 2.2 requires, and nothing more. Only a failure of this tier is a WCAG failure.
The bare minimum
Nothing on the page flashes more than three times in any one second. Unlike 2.3.1, there is no threshold exception for small or dim flashes.
Normative text
Verbatim from WCAG 2.2, W3C Recommendation 12 December 2024. Underlined terms are defined below.
Definitions used (2)
Glossary definitions are normative. Their notes are informative.
- web page
-
a non-embedded resource obtained from a single URI using HTTP plus any other resources that are used in the rendering or intended to be rendered together with it by a user agent
Informative notes (2)
Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.
For the purposes of conformance with these guidelines, a resource must be "non-embedded" within the scope of conformance to be considered a web page.
- flash
-
a pair of opposing changes in relative luminance that can cause seizures in some people if it is large enough and in the right frequency range
Informative notes (2)
See general flash and red flash thresholds for information about types of flash that are not allowed.
See also blinking.
Tier 2 · The gap
Usability & user impact
Where content can meet this criterion and still make things harder for people with disabilities. These are not failures of SC 2.3.2, so raise them as usability defects. Known failures, including failures of related criteria, are listed in Tier 1.
None beyond 2.3.1.
Tier 3 · The golden path
Recommended best practice
The pattern that meets the floor, closes the gap, and avoids audit disputes. A recommendation, not a requirement.
Treat any rapid flashing as a defect.
W3C's Understanding document and techniques for SC 2.3.2 ↗ are informative: sufficient techniques show ways to pass, and documented failures show common ways to fail, but neither changes what the criterion requires.
How SC 2.3.2 maps to the WCAG 3 draft
From this site's reviewed map to the WCAG 3 editor's draft. It's an interpretation: W3C has not published a mapping.
Successor provisions
From WCAG 2.2, section 5.1: “The main content of WCAG 2.2 is normative and defines requirements that impact conformance claims. Introductory material, appendices, sections marked as "non-normative", diagrams, examples, and notes are informative (non-normative). Non-normative material provides advisory information to help interpret the guidelines but does not create requirements that impact a conformance claim.”