Most people buy a shirt for its collar and its colour and then discover the fabric decided everything. Poplin is a tightly woven plain weave, usually cotton, with a smooth flat face and a crisp hand. It holds a collar upright, creases sharply, and looks best either pressed or deliberately rumpled with nothing in between. Everyday cotton shirtings, including twills, voiles and softer washed weaves, sit lower on the crispness scale and higher on the comfort one. They wrinkle less visibly and forgive a day at a desk. Silk is a protein fibre with a natural drape and a soft shine, which is why a silk shirt falls close to the body instead of standing away from it. Washable silk is real silk finished so it survives a cold gentle machine cycle, and it is the practical middle ground if you like silk and do not like dry cleaning. Decide which of those three behaviours you want before you look at a single collar.

Poplin comes out of the wash creased and wants either an iron or a hanger and a steamy bathroom. It is worth it if you like a shirt that holds its shape all day, and it is the wrong choice if ironing is not something you will realistically do. Cotton voiles and washed twills come out softer and can go straight on, which is why they get worn far more often in practice. Washable silk should go in cold, on a gentle cycle, ideally in a mesh bag, and it should never see a hot dryer. Line dry it and press on low with the shirt inside out if it needs it. Untreated silk is dry clean and will water spot, so if you spill anything on it do not dab it with water. Sizing differs too. Poplin has almost no give, so buy for the shoulder and the bust and accept the waist. Silk drapes and can be worn a size up without looking oversized, which is the whole appeal of the loose silk shirt.

A crisp poplin shirt is the most formal of the three and the one that works tucked. It also makes the best open layer over a plain knit, because the structure keeps the front edges hanging straight instead of collapsing. A softer cotton shirt is the everyday one, good half tucked, good with denim, and the one to buy first if you only buy one. Silk is the evening and meeting shirt, and it wants very little underneath it. Anything with a seam or a heavy edge will show through, so a smooth knit tank or a fine ribbed tee is the right choice. If you are layering, keep the piece under an open shirt close to the body and simple in colour. The point of an open shirt is the vertical line it draws, and a busy layer underneath cancels it. Sleeve length is worth a thought too. A short sleeve poplin works alone but not under a jacket, where the seam bunches at the shoulder.

If you are buying one shirt, buy a soft cotton one, because it is the one that will leave the wardrobe. Poplin is the better looking shirt and the one people wear least, so be honest with yourself about ironing before you spend. We like washable silk more than we expected to, though the finish does slightly dull the shine that made silk appealing in the first place, and it is a compromise rather than a free lunch. Skip untreated silk in a light colour unless you enjoy the dry cleaner. If you take one thing away: choose the fabric for the laundry routine you actually have, not the one you intend to start, and the shirt will get worn.