After I posted the chalk stripe outfit, I got a couple of inquiries about the fabric and whether it was rather a pinstripe instead of a chalk stripe. First of all, It is important to understand that there are numerous stripes available,
many of which cannot be categorized precisely. However, the chalk stripe and the pin stripe are not among those.
Probably the most well known stripe today is the pin stripe. It is a very thin (not wider than about 1/18 inch, usually about 1/30 inch wide) single stripe that gives the impression of a pinhead spot. A single warp yarn is used to create a stripe, while the distance between the stripes usually ranges from 1/10 inch up to 1 inch.
Another very popular stripe is the chalk stripe. Here, a series of threads, not just one thread, is used to create a stripe that resembles a stripe that is drawn with tailors chalk. The stripe does not look like little pinhead spots but much rather like a rope. The width of the stripe varies while it is always wider than the pin stripe.
Sometimes you might read that a chalk stripe is by definition a little fuzzy
while the pin stripe is always clear and crisp. This is not convincing. On the one hand, there are many flannel chalk stripes which naturally have a fuzzy effect, but this has at least partly to do with the characteristic of flannel itself. On the other hand, the pin stripe is often used on worsted woolens but there are also flannel pin stripes or fresco pin stripes which are a little fuzzier.
You even may come across the description rope stripe which is supposedly used to define a stripe which resembles a rope. However, many would define this stripe as a chalk stripe since there is no unique distinguishing mark. Other than that, there are numerous other stripes available—shadow stripes, pencil stripes, faint stripes, self stripes—but I will not go into the details since they do not have anything to do with our original question: chalk stripe or pin stripe.
In conclusion, one can say that there does not seem to be a uniform definition for chalk stripe or pin stripe. This is underlined by the fact that some even talk about a wide pin stripe which further confuses the issue. In any case, bear in mind that the name of the stripe is secondary and should not really bother you at all—if you like a certain stripe, just wear it!