Paint in the wizarding world serves both magical and mundane purposes and appears largely identical to its non-magical counterpart. It is a liquid or semi-liquid substance applied to surfaces that dries to form a solid coating. It exists in a full spectrum of colors, seen in various applications from the scarlet paint of the Hogwarts Express steam engine to the gold paint used for the lettering on the Knight Bus. In its mundane form, paint is used for simple decoration and maintenance. Its condition can be an indicator of a location's upkeep, such as the peeling paint on the walls of the derelict Riddle House or the presumably well-maintained state of the house at Number Four, Privet Drive. The most significant form of paint is that used in the creation of magical portraits. This paint, when combined with powerful enchantments, is the key to creating artwork that is sentient and animated.
The primary magical application of paint is in the creation of enchanted portraits. While the artist's skill is paramount, the specially treated paint and canvas are what allow for the subject's personality and movement to be captured.
Other magical uses of paint may include the gold lettering on the Knight Bus, which can appear and disappear, and the hand-painted sign on the ghoul's room at The Burrow, which humorously read “The Ghoul's Lair”.
The history of paint is intrinsically linked to the history of magical art and architecture. The tradition of creating magical portraits has been established for centuries, particularly within ancient institutions like Hogwarts School of Witchcraft and Wizardry and the Ministry of Magic. At Hogwarts, the network of portraits has become a fundamental part of the castle's life and security. The portraits of former Headmasters form a collective of advisors, preserving the wisdom of their time for their successors. This network proved vital during the Second Wizarding War, when Albus Dumbledore's portrait was able to provide crucial guidance to Severus Snape and, later, to Harry Potter. The use of portraits for communication, particularly by Phineas Nigellus Black, highlights a long-standing method of information exchange within pure-blood families and the Order of the Phoenix.
Paint, particularly in the form of magical portraits, plays a multi-faceted and crucial role throughout the series.
According to the Wizarding World website (formerly Pottermore), Hogwarts portraits are created by a wizard or witch artist who paints the subject while using enchantments to capture their personality and mannerisms. For the portrait to be truly lifelike and knowledgeable, the subject must spend considerable time with the artist, teaching the painting how to act and think like them. This is why the Headmasters' portraits are such a valuable resource, as they are deliberately imbued with the wisdom of their living counterparts before their deaths. In the film adaptations, the halls of Hogwarts are famously lined with hundreds of moving and chattering portraits, immediately establishing the magical nature of the world for the audience (film).