DCM lives in the Applications/Utilities folder on your mac When you open it you are presented with a small window, the left of which shows a small zoomed image of what’s under your mouse and the right allows you to choose the type of colours you are interested in. For our purposes as a web developer we want hex codes, so we choose RGB in Hexadecimal (8bit).
The true secret to working this tool into your workflow is the keyboard shortcut to copy the colour as text. To do this, you just hit Apple-Shift-C while the correct colour is shown, this will copy the text of the hexadecimal colour into your clipboard.. something like: “#186231”. This can be pasted directly into your CSS or HTML. It’s somewhat annoying that it copies with quote marks… but still a real time saver.