Chalk stripe, pencil stripe, pin stripe — the differences
Three principal stripe types are used in suiting, each slightly different in character and formality.
The chalk stripe is the boldest — a wider stripe, slightly fuzzy at the edges as if drawn with chalk, typically in a cream or ivory against a dark navy or charcoal ground. It is the most historically formal of the stripe types, associated with British banking and legal dress in the early twentieth century and still the most authoritative of the three. In flannel, it has a soft, classic character. In worsted, it is crisper and more modern.
The pencil stripe is narrower and crisper — a fine, sharp line at regular intervals. It is slightly less formal than the chalk stripe, marginally more versatile, and equally well suited to both navy and charcoal grounds.
The pin stripe is the narrowest — a very fine line, sometimes almost a row of dots, at close intervals. It is the most subtle of the three and the most versatile: it reads as a textured cloth at a distance and only reveals its stripe character on close inspection. A navy or charcoal pinstripe is the safest and most versatile of the stripe suit choices.