Q&A: Reading colour values

Q I need to read and record colour measurements from my photos, using both RGB and L*a*b* coordinate systems, so that I can paste them into a spreadsheet for further analysis. What is the best way to do this?

A Most image editing and analysis apps will provide spot colour values, and some will also average over small areas. However the measurements are often put into a pane which inconveniently vanishes when you switch application, making even manual copying reliant on your ability to memorise the figures.

There are lots of apps in the Mac App Store which claim to provide colour readings from objects on the screen. Most of them will only give you RGB values, leaving you the tedious task of converting them to L*a*b* using an app like BabelColor CT&A.

classiccolormeterHowever the wonderful Classic Color Meter by Ricci Adams (App Store £2.29) will do this job with consummate ease: select its window, move the pointer (cursor) over the area you wish to obtain coordinates from, and press Command-Shift-C to copy the coordinates as numbers. You can paste those directly into your spreadsheet. It supports RGB, HSB, HSL, L*a*b* and other coordinate systems, a range of colour profiles for the conversion, and variable-sized measurement rectangles.