How to find an accessible color by changing lightness only?

Question

Is the following hypothesis true?

For any given color:

{ Hue, Saturation, Lightness_1 }

there exists:

Lightness_2

such that the contrast ratio between:

{ Hue, Saturation, Lightness_1 }

and

{ Hue, Saturation, Lightness_2 }

is at least 4.5.

Bonus question: How could I find such Lightness_2?

[Cross-post](http://ux.stackexchange.com/q/82319/17023) – unor Jul 31 '15 at 17:28 — unor, Jul 31 '15 at 17:28

score 0 · Answer 1 · answered Jul 31 '15 at 13:41

If you install the Google Chrome accessibility developer tools extension, then you will see that the accessibility information for a node whose color contrast does not match 4.5:1 will also include information on what color combination is closest that will.

https://chrome.google.com/webstore/detail/accessibility-developer-t/fpkknkljclfencbdbgkenhalefipecmb?hl=en

The algorithm for doing this is included in the GitHub repository: https://github.com/GoogleChrome/accessibility-developer-tools/blob/master/src/js/Color.js#L267

So, is my hypothesis true or false? – Misha Moroshko Jul 31 '15 at 13:56 — Misha Moroshko, Jul 31 '15 at 13:56

How to find an accessible color by changing lightness only?

1 Answers1