Wedding party
Several outfits that read as a set in a photograph while being worn by people of different builds and preferences.
What governs it. Group photographs. An outfit that works alone and fails in a line of five is a failure, and the line of five is what gets printed.
Where it goes wrong. Matching approximately. Several garments bought from different suppliers in 'the same' colour produce several near-identical shades, which is the near-miss problem multiplied by the size of the party.
Direction. Either match exactly — one supplier, one dye lot, confirmed — or spread deliberately across a clear range of one hue so the variation is obviously intentional. The middle ground is where group photographs go wrong.
In photographs. This role appears in a large share of the photographs. Separate pieces by lightness rather than by hue — lightness is what survives a camera.