Ritual theory
Overview
Imperial magicians who have studied the lore of the realms can use mana crystals to manipulate a realm to create magic effects. The most effective way to do this is to master one or more of the formulaic rituals that are part of Imperial lore, but the outcome of these rituals is fixed. If a magician wishes to achieve an entirely new effect, something not contained in Imperial lore, then they will need to prepare an arcane projection to create the spontaneous ritual effect.
A good understanding of the theory of ritual magic is essential for creating effective spontaneous magic. There are the known laws of magic that govern the rules by which it operates, as well as its limits and the role of eternals in magic. Having a good working knowledge of the laws and limits of magic is crucial when creating or discussing magic in Empire.
Resonance and Dissonance
Ritual magic is not limitless in scope and there are a number of fundamental laws that are common to all the realms, and certain limits that it cannot easily overcome. In addition to this, each of the six realms (Spring, Summer, Autumn, Winter, Day and Night) have strengths and weaknesses, referred to as resonance and dissonance. Where a realm is resonant with a theme, rituals that produce that outcome are easier to cast using that realm than any other. For example, the Spring Realm is resonant with healing magic, so rituals that heal the wounded are easier to perform using the Spring realm than any other realm.
Where a realm is dissonant with a theme, then it is much harder to create a ritual effect that produces that outcome, if it is even possible. For example, the Autumn realm is dissonant with healing magic, it can repair broken items and damaged buildings, but it has almost no ability at all to heal the wounded.
Laws
Limits
There are fundamental limits on what magic can achieve that are well known and understood. Magicians across the Empire have spent centuries searching for ways to surpass these limits and never found a reliable way to overcome them. Having a good working knowledge of these limitations is a good way to demonstrate your characters skill with ritual magic.
In the game, the limits of magic are absolute rules for the game. While anyone can play a character that is striving to overcome one or more of these limitations, that is not a character goal that will ever be fulfilled. These limits are reflections of the game rules, so any arcane projection that is submitted that tries to break one of these ruls will fail. For that reason, it is always better to check any arcane projection against these limits before you submit it.
Divinations
Normal divination rituals use the power of the realms to glean useful information. The Day realm with its emphasis on predictability, facts, and figures, provides measurements and known quantities. Divinations in other realms are usually similar, providing specific information of interest to that realm, such as the Autumn ritual Ties that Bind which lets a magician discover details about a bonded item they have an intimate connection with.
Divinations of the Night realm are unusual because the disordered chaotic nature of this realm means that divinations that draw upon it tend to provide unpredictable answers. Responses are often in the form of riddles and symbolic visions, as in the Signs and Portents ritual. These rituals tend to provide secrets and mysteries, or at least omens of them, as they have been detected by the Night realm. The realm itself makes no attempt to understand or prioritise these secrets, it only perpetuates them.
In neither case is it possible to create a ritual that asks a question of the realm itself. The realms are not sentient and they cannot analyse information to provide conclusions, opinions, or judgements. The only way to create such a ritual is by involving an eternal of that realm. There are only a small number of such rituals currently in Imperial lore, the most notable being Swim Leviathan's Depth which asks Leviathan to answer a specific question. Leviathan will answer the question, but can only do so based on the knowledge it has. Involving a sentient agent in this way makes it possible to achieve something that would not normally be possible, but at the risk of Leviathan not knowing the answer or even simply being wrong.
Arcane projections for spontaneous divination effects must specify very precisely the information that is wanted and the subject of the divination. Such projections cannot be used to glean other information or even be cast on a different subject. Only formulaic magic possesses this degree of flexibility. For example, it is easy to make an arcane projection that determines information about the history of a specific item; it is not possible to create an arcane projection that lets the ritualist perform that spontaneous effect on any item.
Divinations that deal with esoteric information are likely to only ever exist as spontaneous magic that targets a specific named item - one where we can be confident the desired information exists. Likewise it is only ever possible to use divination magic to gain information the referees have reliable access to.
Lost Items
Items that are lost or missing cannot be found using magic. There are eternals that may know where an item is, most notably Kimus, but it is not possible to use an arcane projection or ritual to find a specific item that is missing. In general, if a plot requires you to find a lost item, then magic categorically won't solve that problem for you - to find a lost item you need to speak to whatever character or being knows where the item is and persuade them to give you guidance.
Current Events
Divinations are only effective when looking at events and objects that are recent. This need not be current - you can divine things that happened in the last few days, the last few seasons, potentially even the last few years if their effects are still resonating. But you can't use ritual divination to obtain information about the past without a specific focus to the events of the past.
A spell like Hand of the Maker works because it is cast on the item in question. That item is the link to its own past, and so it is possible to use the item which currently exists and is in your hand to find out about how it was made. Or you can use Skein of Years to find the dramatic and important events from the item's history. Without the item in question, neither ritual would be remotely possible.
Rituals like Swim Leviathan's Depth work because they allow you to ask an eternal creature what it knows of the past. The ritual does not divine that information for you - it puts you in contact with an eternal that might know the answer.
This limitation of divinations exist to preserve the mystery and intrigue of the setting. The wiki in particular includes hundreds of descriptions of notable places that are associated with legends or mysteries. There is no current plot for most of these locations - they exist to inspire us to write plot with them in the future. The moment we do so, you will be able to use divination magic to investigate that mystery. That will work because the very fact that we are doing plot with it means that there will be contemporary events which can be the subject of divination. But if there is no plot to find out more information about - if there are not current events to divine - then there is no more information to give out than is already on the wiki, and the divination will fail.
Maps
Maps are a powerful hearth magic, symbolic representations of a location that allow a magician to perform magic that will divine information about the place in question. All scrying rituals that operate at the territory level require a suitable map before they can be performed. Any attempts to create a ritual that scries an area without using a map will fail.
It is not possible to do the opposite - to use divination to create a map of an unknown territory. If such a thing were possible it would instantly circumvent the restrictions on scrying in general - magicians would simply need to create the map first, then use it for the following divination. This isn't possible - you can never create a map with magic.