A recent journal-published peer-review of APCA:

"...15 years since the adoption of WCAG 2.0...enhanced color models adapted to human perception, have been developed...APCA shows more accurate results for measuring color contrast..."

#a11y #Webdesign #accessibility #color #colour #contrast #APCA #WCAG3 #WAI

https://doi.org/10.1007/978-3-031-35992-7_53

For the "it's the law tho" crowd, here's a fix:

APCA to WCAG 2 Backwards Compatibility Chart

For 4.5:1

Backwards 4.5:1 is achieved when:

IF the lightest color is darker than #d0d0d0
OR the darkest is darker than #595959
THEN Lc ±60 exceeds 4.5:1

ELSE Lc 72 or Lc -77 exceeds 4.5:1 in all cases

---
For 3:1

Backwards 3:1 is achieved when:

IF the lightest color is darker than #c4c4c4
OR the darkest is darker than #6c6c6c
THEN Lc ±45 exceeds 3:1

ELSE Lc 57 or Lc -63 exceeds 3:1 in all cases

---
Here's the implication:

If both colors are darker than #d0d0d0 or at least one is darker than #595959:

Then it's not a matter of "can you?" use APCA, it's a matter of you *should* use APCA.

For color pairs darker than #d0d0d0, WCAG 2.x contrast math results are not meaningful, and create inaccessible, often unreadable, color pairs.

Actual Accessibility is where it's at.

#darkmode #Webdesign
#a11y #color #webdev
#colour #wcag #apca

@djangonaut the lighter blue might be compliant to #WCAG 2 but you might be surprised at the results for upcoming #WCAG3 aka #APCA : it requires a minimum font size of 107px !

https://www.myndex.com/APCA/?BG=537689&TXT=000000&DEV=G4g&BUF=A22

Recent positive, independent peer review of APCA:

"...15 years since the adoption of WCAG 2.0...enhanced color models adapted to human perception, have been developed...APCA shows more accurate results for measuring color contrast..."

#a11y #Webdesign #accessibility #color #colour #contrast #APCA #WCAG

https://doi.org/10.1007/978-3-031-35992-7_53

Recent positive, independent peer review of APCA:

"...15 years since the adoption of WCAG 2.0...enhanced color models adapted to human perception, have been developed...APCA shows more accurate results for measuring color contrast..."

#a11y #Webdesign #accessibility #color #colour #contrast #APCA #WCAG

https://doi.org/10.1007/978-3-031-35992-7_53

Recent positive, independent peer review of APCA:

"...15 years since the adoption of WCAG 2.0...enhanced color models adapted to human perception, have been developed...APCA shows more accurate results for measuring color contrast..."

#a11y #Webdesign #accessibility #color #colour #contrast #APCA #WCAG

https://doi.org/10.1007/978-3-031-35992-7_53

The following info graphic is intended to demonstrate the nature of human contrast sensitivity, using text samples to connect the abstract science to practical reality.

It's based on infographics I originally created several years ago, but it recently got a bit of attention on Twitter, and I'm reminded that there's still a need to distribute this knowledge.

More info and description in the ALT

#a11y #accessibility #color #contrast #apca #webdesign #typography

LEGALLY READABLE (a thread)

APCA is not official per WCAG 3 yet, as WCAG3 is undergoing major changes, particularly to the conformance model.

However APCA is also an independent standard as part of the IRT-RC (Inclusive Reading Technologies Readability Criterion), this is useable per the public beta, and comments are encouraged.

In the majority of the world in most contexts, WCAG 2.x is not strict "law" and designers may use alternate standards. Including the USAB-508 under the "alternate facilitation" rule. (Regions or contracts vary so determine your requirements).

Considering the serious flaws in WCAG 2.x contrast, those who can should be encouraged to use standards that promote actual accessibility, such as APCA/IRT-RC.

(continued...)

#a11y #accessibility #color #colour #contrast #WCAG #APCA

I have been working on contrasting colours recently, making heavy use of https://www.myndex.com/APCA and I commend to you the colours #163d16 vs #bfc7a9 for all your swamp with signage needs.

#APCA

@Gargron please keep the background and text colour accessible #a11y but not over saturated

Lc value calculator: https://www.myndex.com/APCA/

Why #APCA as a New
Contrast Method?
https://git.apcacontrast.com/documentation/WhyAPCA

More resources:
https://colorusage.arc.nasa.gov/guidelines_lum_cont.php

An interesting, in-depth look by University of Cambridge’s Inclusive Design Tools Group at the W3C WAI Web Content #Accessibility Guidelines (#WCAG) contrast formula and proposed changes based on the Advanced Perceptual Contrast Algorithm (#APCA).

https://www.cedc.tools/article.html

#A11Y