There is more than one way to skin a cat. Ignem is indeed one way to do it, but Imaginem is also effective. The shadow is specifically a species, and thus can be manipulated, created, or eliminated by Imaginem.
A shadow is where the light is blocked by an object. The Species however may become invisible, but this under the medieval mindset does not mean it is truely transparent.
Pe/Ig could flood the whole area with shadow (bit obvious) or a few Cr/Ig spells centred on the magi would create light and probably hide the shadow during the day, but if he's walking through at night the moving lightsource negates the invisibility. clever Re/Ig may move the light around the magi.
Actually, a shadow is the lack of species. Species are produced when light falls on a substance. A shadow is caused by the imposition of an object in front of another, stopping the light falling on it and preventing the excitation of species. This is why invisible people still produce shadows - they have no species of their own, but they are still opaque to light.
There are still multiple ways of removing a shadow. A Creo Ignem will create a light source wherever the caster desires, so this will allow light to fall on the shadow and remove it; but might also cause further shadows in a different direction unless the light is very diffuse. A Creo Imaginem could create fake species which match what would have been seen if the object wasn't blocking the light, and thus cover up the shadow.
[I imagine this to be relatively difficult. Everytime the person moves, the fake species would have to move to exactly match the blocing object. Thus the spell would need to be 'intelligent' to detect the changes in real time, or be controlled by the concentrating magus. Or else, it could be a simple task, depending on the needs of your saga.]
(A Perdo Imaginem is needed to create a specific shadow, and a Perdo Ignem will create generic shadow or darkness by reducing light)
If you can sell your soul to the devil you might sell your shadow as well...
Or you sell your soul and the devil takes your shadow in return...
Only recommended for real evildoers who are needed to be marched...
A twilight experiance might make you loose your shadow (for some time...).
Can shadows be animated and "walk away"? If not by Hermetic magic, maybe by Fay Magic?
You can do it a lot of ways, but you probably want to do it with CrIm. That way, an item that makes you completely invisible with no still cast shadow is just Cr(Pe)Im, rather then Cr(Pe)Im(Ig). It's just one less requisite for the same effect and same level.
From what I can infer from the guidelines, Imaginem spells won't really change light levels, so I would rule out directly affecting the shadow or the shadowed area with that kind of spell.
A ReIg spell that bends light sounds pretty good, but the book doesn't really give guidelines for that. I guess because the people of the middle ages didn't think that way...
A MuCo spell that lets light pass through you sounds awesome, and would even confer invisibility on its own. MuCo spell guidelines need to be beefed up in general so it is clear what abilities can be given. But I have a nagging suspicion that making yourself transparent = destroying your transparency = Perdo Corpus. (?) And that means at least level 40.
The best minimally effective CrIg spell I can think of to remove your shadow is level 25: Base 5 to create sunlight, +1 Diameter, +1 Part to only cast light in a certain direction, +1 effect for the cast light to match the shape of your shadow, and +1 effect so the light will adapt in strength for changing light levels. Lower levels could be enough if you avoided direct sunlight.
How about a MuIg or PeIg spell that temporarily makes light pass through things as it gets near you? Any takers?
I think that it is possible, as guidelines for the toughest PeCo spells cover "destroying a property of a person" like weight or solidity, so I was thinking maybe opacity as well, but all of these are kind of a stretch.
Yeah, I can definitely see MuCo changing you so you are completely transparent. Do you think that would be equivalent (in level) to making yourself insubstantial, or would it be easier? Turning yourself into movable glass (obviously difficult enough) isn't good enough because the light will bend as it goes through you and not go where it's supposed to. You'd have to... just... metaphysically change the property of your substance into that which does not stop light... somehow.
I hope that in ArM6 the MuCo guidelines are a little more clear about abilities. (It would also help to outline DISabilities, like the ArM4 spell "Magus's Mask of Flesh" which melts your enemy's face. Someone should start a new topic for that.)
Here's another possible shadow removal spell:
ReIg 20 - Cause all light to bend around you as if you were not there. Base 10 to move fire in a very unnatural fashion, +1 Diameter, +1 Touch.
More than one way to skin a cat indeed, and thus the award-winning beauty of this system. 8)
There are several ways that I see to replace the species (aka "light") that is blocked by a natural body (the magus').
Change the nature of that body - making it "truly" transparent, taking on a property of air (Aurum), or perhaps clear water (Aquam). Giving a body such a property is not a low-magnitude change.
Bend the species/light around the body, so that it lands where it would have had the body not been there - probably harder than it sounds, but certainly doable with enough Rego and creativity.
Create the species that is blocked, but where it would have been at exactly the missing level - that is, "fill in the shadow" perfectly. This might require an Intellego req' to get it "just right" as the conditions change with movement and so on.
Imagonem and a wide brush - simply "paint over" the scene, so a shadow is never an issue, and the scene "appears" the same to the senses. Easier said than done, but again, doable.
Mentem - distractions work wonders. People don't see what they are not looking at. Perdo to forget what you see. So many possibilities.
I really think that removing "opacity" with PeCo is the easiest way to do it.
Incidentally, it is not natural for the human body not to be opaque, so I believe (serf's parma) that if cast with momentary duration the spell will not last forever, but only an instant.
Hmm, i thought that would be how it worked if it was Muto...
But i might be totally wrong on it.
It should be enough to create light opposite to whatever light sources exists, not sure how detailed it has to be before requiring the In requisite?
We know from reality that light can be an excellent camouflage, it has been used on both land vehicles, ships and aircrafts very effectively and the light used requires surprisingly little "precision aim" to work.
I would say its possible to aim a spell at the shadow and have the effect be that the spell "lights it up", removing it without needing any direction...
My thought re the In requisite is that, while moving, the species ("light") varies - simply adding a constant amount would work for a static situation, but once you move the effect would either glow or be slightly ineffective, depending on how much ambient light was around the next corner. On a bright day your shadow appears dark, but actually has a lot of light in it - turn down a shady alley, or have a cloud pass overhead and it's all different. The In requisite would monitor the situation and adjust accordingly.
Same with the Imagonem - fine for a static situation (some very interesting effects can be achieved statically), but if we're talking about walking around and varying backgrounds, light, degrees of motion - easier said than done.
I've never been too clear over the assumption that adding an Intellego requisite allows a spell to be 'intelligent' or 'adaptive'. That is not normally a function of Intellego. Is there a canon precedent? I'm not saying it's wrong, it's just I can't see the logic in it.
If anything, the CrIm guidelines tell us that moving images add a magnitude, and you can use concentration to make them move as directed. I would say that the spell could cope with minor changes in intensity and shape, but should the magus move from a sunlit street to a dark alley, he'll have to concentrate momentarily to adjust the spell.
On the other hand, I can see an invested item here: an Intellego spell detects whether the light level has changed, and a linked trigger to a new Creo Imaginem (or whatever) effect makes the change. It's a rather complex way of doing it, and not quite the same as having an adaptive spell as per the proposed Intellego requisite. It would also need to be an enchantment rather than a spell. However, I realise this weakens my former (mild) objection.