<https://s-ink.org/colour-perception-background-colour#primaryimage>
<http://schema.org/contentUrl>
<https://i0.wp.com/s-ink.org/wp-content/uploads/2021/09/ColourAndLightnessPerception.png?fit=3830%2C2096&ssl=1>
<https://s-ink.org/colour-perception-background-colour>