A Beginner’s Guide to Drucraft #24: Light Sigls (II)

A further overview of Light sigls.  This section concentrates on one of the most coveted and widely used powers of Light drucraft – invisibility.

Diffraction

Sub-branch:  Manipulation
Type:  Triggered
Appearance:  Blue, transparent
Rank:  C to B+

Bends visible light around the subject, creating a bubble that light cannot enter.  Some diffraction sigls do this by directly bending the light rays, while others temporarily alter the light’s wavelength for long enough for the wielder to hide in the ‘trough’ of the wave.  The second approach is usually considered more elegant, but the first is simpler to do.  Since the light is bent, rather than suppressed (as happens with negation sigls) anyone looking at the wielder sees whatever is behind them.  This allows for ‘true’ invisibility, rather than creating shadows or darkness.

Diffraction sigls are by far the cheapest of the true invisibility sigls, but they come with significant drawbacks.  First and most obviously, diffraction sigls stop ALL visible light from reaching the wielder . . . including the light that would have reached their eyes.  This means that a diffraction sigl, used on its own, blinds the wielder.  Some diffraction sigls attempt to remedy this by allowing a small amount of visible light to reach the area around the wielder’s face, but this still hampers vision, and also means anyone looking at the wielder will see what looks like a disembodied head hovering in mid-air.

A more effective solution is to have the diffraction sigl exclude visible light, but not other frequencies.  (This is normally going to be the case anyway, as the average diffraction sigl doesn’t have the power to screen out the entire electromagnetic spectrum.)  The diffraction sigl can then be paired up with some sort of vision-enhancing effect to let the wielder see in the ultraviolet or infrared range.  This is fairly reliable, but does mean that the wielder has to pay for two sigls instead of one, both in terms of money, and in terms of essentia capacity.  Sigl providers are notorious for selling diffraction sigls at what seem to be reasonable prices, then gouging customers on the vision sigl that goes with it.

Even once the vision problem is solved, diffraction sigls are by no means perfect.  Since the diffraction effect tries to bend light around the wielder, they run into problems when the light’s new course would take it through an opaque object, such as the ground – anyone looking closely at the feet of someone using a diffraction sigl will notice something odd.  For similar reasons, the diffraction field works poorly at close range – the closer a viewer comes, the more they’ll be able to make out a sort of ‘goldfish bowl’ distortion.  Both of these effects are much more noticeable in bright light or if the wielder is moving, and especially if the wielder is moving quickly.  Someone trying to run under a diffraction field in broad daylight may actually be more obvious than if they weren’t using a sigl at all.

Despite these drawbacks, diffraction sigls remain popular.  If you want to be invisible and can’t afford a transparency or active camouflage effect (which most people can’t), a diffraction sigl is usually the only practical option.

Transparency (Matter)

Sub-branch:  Transparency
Type:  Triggered
Appearance:  Pale to very pale pink, transparent
Rank:  B to A

Alters the transparency of the wielder, causing visible light to pass through them.  Often grouped with Light sigls, due to its effect, but this is a Matter sigl and as such is described more fully in the Matter Sigls category.

Active Camouflage

Sub-branch:  Duplication
Type:  Triggered
Appearance:  Almost perfectly clear, with a hint of blue
Rank:  A to S

This powerful sigl intercepts all outgoing light in a similar manner to the Shadowman sigl, but then replaces this light with a copy of the light approaching the wielder from the opposite direction.  So, if the wielder is standing facing north, any light radiating away from their body northwards is instead replaced by a copy of the light coming in from the south.  Thus, anyone looking at the wielder sees what they would have seen if the wielder hadn’t been there.

This sigl is generally considered to be the pinnacle of invisibility drucraft, providing perfect all-round concealment with no disruption to the wielder’s vision.  It is, however, extremely complex and power-intensive, and only the most powerful Light Wells are capable of producing one.

The sigl has no real weaknesses.  It can screen out both visible and invisible parts of the spectrum, and despite its power is only moderately demanding on the wielder’s channelling skill.  Some versions of the sigl struggle to maintain perfect camouflage while the wielder is moving, creating a faint visual distortion in the rough shape of a human body, but higher-quality versions eliminate even this flaw.  However, its price puts it out of range of all but the most wealthy.