The scene: a Mac user is trying to test color contrast with a tool like The Paciello Group’s Colour Contrast Analyser. When they grab a color using the color picker, it doesn’t match the HTML/CSS define color being used. It is common for the Adobe Software users on Mac to change the display settings to more accurately represent the colors of printed material.
When testing Web Accessibility Standards, color should be set to match a visual display. To do this, we must make sure that the Mac Display Profile is set to sRGB IEC61966-2.1 which is an RGB color space created by HP and Microsoft to use on monitors, printers and the internet. This will ensure that the CCA will match the colors defined for a digital display.