Headed by titular Dean Rime Ginsey, the Arcanum is an Empire-spanning organization that manages the training of arcane spellcasters. Many are wizards, but there are still some warlocks who take up Pacts with the Archfey, and there are always sorcerers being born among all species, but particularly among dragonborn.
There are some general principles at work at Arcanum headquarters as well as their various franchises and charter schools. One is that authority is represented by a consistent color-coding based on the spectrum of light as viewed through a prism.
Violet “pledges” are those who have enrolled in an Arcanum school but who have yet to demonstrate consistent arcane abilities
Indigo “students” have demonstrated some facility with arcane magic, but have yet to earn a place in apprenticeship
Blue “’prentices” who have “taken the blue” are sworn to a lead instructor who will train them in the basics, form them in discipline and character, and help them in their independent study project. This project may involve them going out into the world – in fact it often does. This is also the minimum accomplishment to enable one to enroll in the Imperial Army Arcane Corps.
Green “proven” are apprentices who have completed their independent study project and been examined thoroughly by the faculty. They are given much more freedom and leeway in their studies.
Yellow “adepts” are powerful arcanists who are also eligible to join the faculty of an Arcanum school.
Orange “sages” often take the saffron-colored robes and stop there, devoting the rest of their lives to study and reflection. A sage is often the head of the faculty of an Arcanum school.
Red “guardians” are the highest ranked arcanists in most circumstances. They are responsible for arcane and planar security, as well as protecting the most powerful magical relics in the Empire.
White is the highest rank, left for powerful figures like Rime himself, Abalaster, Celodel and similar “luminaries.”