In the eyes of most, channelling is the point at which one becomes a ‘real’ drucrafter. Someone who can only sense is technically a drucrafter, but they’ll never get much respect until they learn to channel as well.
At its core, channelling is just mastery over personal essentia. All living creatures have a personal essentia reserve – the essentia that drifts naturally into their body and attunes to them. This essentia is very limited, but it constantly replenishes itself as more flows in. Attuned essentia has a connection to the person it is attuned to – it can be used to activate sigls, and, with practice, can be controlled.
Learning to control one’s personal essentia is a slow process, but it’s not as hard as sensing. Once a drucrafter has learnt to feel their own personal essentia the toughest part has already been done – they still need to learn to direct it, but the fact that they can get feedback on their efforts and see/sense/feel when something is and isn’t working makes the process much, much easier than it would be if they had to fumble blindly. It’s much like learning how to use a muscle – it takes a long time, but ultimately it’s just a matter of practice, and just as a baby eventually learns to use their hands to grasp and manipulate things, a drucrafter eventually learns to move and control their own personal essentia, clumsily at first but with greater and greater confidence and dexterity the more they practise.
Being able to control one’s personal essentia is necessary for drucrafting because most sigls don’t work on their own. A minority of sigls, known as continuous sigls, activate automatically simply by being worn on the body – they will naturally pull in personal essentia and keep on pulling in more and more of it until they hit their limit. However, this is an extremely crude and mindless way of activating a sigl, and carries significant drawbacks. A sigl can’t think, and has no way of knowing when it’s the “right” time to activate itself, which means continuous sigls will keep on trying to work no matter the situation. Sometimes this is simply annoying, such as a light sigl shining in broad daylight, and sometimes it’s actively harmful, such as a strength sigl amplifying your muscles when you’re trying to do something delicate. On very rare occasions it can even be actively dangerous – draining your personal essentia too far for too long has various negative health effects, particularly if a drucrafter is already sick or injured. In addition to this, many drucraft effects require far too much fine control to work as a continuous sigl – as a rule, anything more complicated than “on or off” is not going to be a good choice for continuous operation.
For these reasons, most sigls are designed instead to work on a trigger. Triggered sigls stay inert until a matching flow of personal essentia is channelled through them, at which point they activate. The essentia flow works as an on/off switch – supplying essentia turns it on, cutting off the flow turns it off. Many sigls also are designed to work with varying levels of power – these sigls, sometimes called “variable sigls”, allow a channeller to achieve a very easy level of control over the sigls’s power by increasing or decreasing the essentia flow.
Many sigls, however, require much more complex inputs than simply increasing or reducing the power. Effects such as optical cloaks, spatial manipulation, jump and flight spells, or healing all require quite precise and varied inputs from the drucrafter – the sigls are typically designed so as to accept slightly different types of essentia, channelled in different ways. Mastering these sorts of sigls requires both broad channelling skill (to reach a certain level of finesse and precision with essentia flows in general) and also specialised knowledge of the sigl in question (which typically can only be achieved with practice). While a competent channeller can figure out how to use a basic triggered or variable sigl in a matter of minutes, the more complex sigls can require weeks or even months to achieve any real mastery.
There is no real cap on the level of skill that can be attained with channelling, and for those who decide to devote themselves to it, mastering it is a lifetime’s journey. This, however, is very rare – the vast majority of channellers learn as much as they need to operate the sigls they have, then stop.