The Nightmare of Sigil
To the nobles of Sigil, masks are an essential part to ones outfit. To go outdoors without one's mask is arguably worse than stepping outside without your under garments.
There are several types of masks in Sigil, with their own purposes. All are customized, personalized for each individual, and can only be purchased and made by licensed maskmakers.
***Note: It should be mentioned that it's extremely frowned upon to use any magic on masks to enhance their looks. Illusory designs or other glamours added to masks is seen as cheap, gaudy, and distasteful. While not inherently against any actual rules, it's strongly taboo within social circles.
Each mask has a 'grade', features that distinguish their wearer's rank in class. Masks are used not just to separate nobles from the city, but to separate nobles from each other based on class.
Most obvious at a glance is how much of the face is hidden. The higher class a noble is, the more of their face is hidden. Masks can hide as little as just the eyes, or at their highest grade cover the entire face and parts of the neck.
Their designs are a display of wealth, as the more complicated or material heavy a design, the more money was put into the mask. Because of this, certain maskmakers are often more sought out than others for their taste in design, or their access to materials.
The most displayed type of mask, daymasks are exactly as their name suggests: the mask a noble wears during their outings. Made from sturdy materials such as leather, these masks are the essential public face of a noble.
Daymasks are characterized mostly by colorful but harmonious color schemes, flaired accents such as feathers or gems, and being built to last long (a year or longer).
Similar to daymasks in use, evemasks are reserved specifically for special outings in the latter part of the day such as theater performances and formal dinners.
Evemasks, unlike daymasks, are built for elegance and tend to be far more simplistic in design. Noted by their dark colors with few, rich accent colors, evemasks have little to no accent materials and are very simple in shape.
Also known as characters, or ball masks, masquerade masks are extremely flashy and detailed masks that are used specifically for balls.
Masquerade masks are known as one of the most expensive products in the entire city, due to their eccentric design and creation. Very few maskmakers are respected enough to create masquerade masks.
Generally, masquerade masks are made to look like animals, though they can also look vaguely like people, or plants, or even designed in ways to represent ideas or places. Heavily adorned in decorations such as feathers, scales, gems or cut leather, and often extremely colorful, masquerade masks are made to impress.
Unlike daymasks, it's not uncommon for a single noble to own several masquerade masks due to the cultural significance around them.
Masquerades and balls are events where nobles revel in their own company, but every attendee is required to show in masquerade. They come in character, based on their mask. Often regarded as a high class game, it serves to create an atmosphere of meeting new people, or trying to guess who each character is under the mask. Buying and attending in a new character is often a highlight of the year for a noble.
The only type of mask that is allowed to be worn by lower class individuals without punishment, theater masks are to be used specifically when practicing and performing for a stage performance (and only within that theater's premises).
Designed to be recognized as a theater mask from a distance, they're painted solid, bright colors and molded into emotions. No details are painted onto full theater masks.
There are pseudomasks in theater, when details are needed (such as a lion mask). When these character details are needed, the masks are designed in such a way the face is always visible, and the mask sits around or on top of the head instead.
There is a massive stigma to lower class individuals wearing masks, and many steps are taken to ensure they never will.