Light and the visual sense


I wonder if blocking light and blocking sight are a single or separate properties of stone.

I.e. can I have a room or building that has no windows, cast PeTe to destroy the property of stone that blocks light but not the property that blocks visual species and have a well illuminated place?


A Window of Singular Direction from HoH:TL 141 (MuTe10) might do what you're after. There is no explanation of the Base 3 guideline use in the book. The errata clarifies that it should be +1 mag for stone:

So if earth can be rendered unnatural enough to be permeable to light in on direction only at Base 3, then PeTe cold probably do that too (? although probably not in a single direction?). Suggest you go with MuTe as its got a Core rulebook ref, or go with a PeIm spell which could also do the same thing.

A recent one of several discussion of invisible objects on this forum is here and refers to this. It starts from

A stone not blocking light/lumen would in general hence not block the species carried in it.

But could it be made to do so with PeTe? That change to the stone would be less about the stone (transparent/intransparent) than about the species carried in the light/lumen passing through it. So this is unlikely to succeed with PeTe.

Could it be made to do so with MuTe changing the stone into something highly unnatural? That looks like just changing a stone into something doing something highly unnatural - stripping species - to something unrelated - namely the light/lumen - just passing through the stone. Couldn't you, by following this pattern, then MuTe a stone into something doing just about anything to objects it touches? Best ask your troupe - but I wouldn't permit it.


EDIT: It is possible to change stone to semitransparent milk glass. This cannot be seen through, but still lets part of the light pass. Such glass is known since antiquity: look up e. g. the Lycurgus Cup to get further ideas.

Ok, separating opacity for light and visual species seems to be problematic... What about destroying the "blocking light/species" property? Making a "window" into a wall (while keeping the wall intact regarding heat, physical force, etc. should then pretty simple (base 1), correct?

Turn the wall into an enchanted device with a Perdo Ignem effect to momentarily destroy the ability of light to carry species? Combine with a separate spell destroying the ability of stone to block light.

Quite a bit of effort, but other than that the main problem I can see is getting the Perdo Ignem effect to work for the right length of time - you want it to prevent the light carrying species through the wall, but presumably you then want it to be able to carry species normally once it is in the room.

Of course you can. It's called magic for a reason.

There is no Perdo guideline to destroy only a property of a solid. If you have to search for similar guidelines in other forms, the only thing that strikes to me to be similar is this Corpus guideline: Level 40, destroy one property of a person, such as their weight or solidity. IMHO, it is justifiedly difficult to remove that one property.

Muto is probably easier, as ironboundtome has said. But you have to deal with the impermanent nature of that type of magic.

There is PeAq15 as well.

Damn, the Perdo variant will have the same problem... Just found

in ArM5 p. 78

Yes - that the ability is only temporarily suppressed for the duration of the spell is a good thing, as you want the light to start being able to carry species again once it's in the room.

So you destroy its ability to carry species just long enough that it drops all of the species it was carrying already, and then once the duration wears off, it behaves normally again - but it's still lost all of the species it was carrying previously, so you can't see what's on the other side of the wall.

Whoops! You are right. And probably it is a more applicable guideline than the corpus one because it is designed for some inanimate object instead of a living thing. Add one magnitude to affect stone and you have a base of 20 to which you will have to add duration and size (+ 1 magnitude for touch if it is an spell and not an enchantment).

I think that it is still easier with Muto.

What about "Level 5: Destroy one aspect of dirt, such as its weight or its cohesiveness" from HoH:S, page 37?

Could a Muto Imaginem spell change species for sight so that they could travel in another medium, like air waves or smoke? So that even in the absence of light one could see the object that is emitting the altered species.

See HoH:S p.65 box Synaesthesia Examples: "Spells that transform the species that trigger one sense into those that trigger another have a base level of 2." So you could transform the iconic species into echoic species, which you then can hear even in darkness.
You need to sense the species to be transformed first, of course. This is hard for iconic species never emitted for lack of light. Touching the item (T: Ind) or room (T: Room) that would emit them, were there any light, might be sufficient - or not. That depends on the detailed process of generation of iconic species in ArM5 - which I don't know of.
But Eyes of the Bat (ArM5 p.127) might be easier to get for most magi.

True. I was curious about creating an object that everyone (not just magi) could see within a completely darkened room. A spell could be cast on the object well before it was placed in the dark room.

The Synaesthesia spell guideline does raise another question however. As opposed to the ArM5 Imaginem description on page 79:

"Imaginem spells affect the process by which species are produced, rather than the species themselves. Thus, the species emanating from an illusion are not themselves magical."

…it would seems that echoic species are indeed magical and would be resisted.