The RGB values are the amounts of red (R), green (G) and blue (B) that combined make up the measured color. The values are from 0 (lowest) to 255 (highest).
A RGB value is relative to a color space.
Yes. Select the desired color space in the Digital Color Meter’s drop-down menu; choices include various standard RGB color spaces as well as the human-eye L*a*b color space.
A color space contains all the colors a specific device can produce and a method to express them. Specifying the color space together with the RGB values lets you reproduce the same color accurately across devices.
Choose a color space that the device where you want to use the color supports.
The L*a*b color space contains all the colors the human eye can see. Instead of using red, green and blue, L*a*b defines colors as brightness (0–100) — L — , colors from red (-128) to green (127) — a — and colors from blue (-128) to yellow (127) — b.
Yes, though Digital Color Meter itself will not do that for you.
Turn to a site like Colorizer to enter the values gained from Digital Color Meter and have them converted to the color space and specification you need.
(How to use the eyedropper tool to identify the color of any pixel on screen with macOS tested with macOS Big Sur 11.0 and macOS Catalina 10.15; updated November 2020)