When the maximum value is odd...

When a quantity is measured as an integer in a range from zero up through some maximum value and that maximum value is odd, then 50% of the maximum cannot be expressed as an integer.

This aspect is simple and obvious when you're thinking about it but sometimes it can get overlooked, starting you down the slippery slope of letting sloppiness leak into your technical writing. For example, I once saw a technical reference document refer to #808080 as having 50% brightness.

Examples#

MIDI intensities#

In MIDI messages, .note_on intensities are integers in the range [0, 127].

24-bit RGB colors#

In 24-bit RGB colors (8 bits per channel), intensities are integers in the range [0, 255].

255 is divisible by 5#

Fun fact: 0.2, 0.4, 0.6, and 0.8 of 255 can be expressed as integers, because 0.2 * 255 = 51 = 0x33.