I have gotten confused with Ignem and Imagonum again.
Can a mage use ReIm to create a mirror effect?
Or is it a different Art combo?
In the medieval paradigm, light provokes emission of species which is what people see - so mirrors are a bit weird.
They appear to reflect both species and light in a way which depends on their appearance (a lump of metal might not be a mirror, but the same metal would be if flattened and polished)
In this sense it would be logical to say that a mirror is a CrIm effect (possibly with an extra magnitude) since it otherwise would be a ReIm(Ig) for making a surface behave like a mirror or a Cr(Re)Im(Ig) for creating an illusion of a mirror and both of these seem to complicate things more than necessary.
I would go with CrIm and possibly +1 magnitude for the mirror effect.
1 Like
Perhaps the original query was too broad.
Take the cut down, related example of: if a mage could displace her image one pace forward, she could then see her own back.
But what if she wanted to turn the displaced image around, in order to see her own front side.
1 Like
There are not many ReIm examples, and the ReIm guidelines do not specify turning an image around explicitly.
But the Image from the Wizard Torn would move very weirdly if it couldn't turn. 
2 Likes
I don't see why not?
Probably easy enough for spontaneous magic even.
To create a magical mirror spell, I would go for Creo Imaginem (to create the reflection), with a requisite of Muto (to have the reflection changing) and two more magnitudes, one for changing image, one to have the change match the movement (As in Wizard's Sidestep, core p.147)
For me the Muto requisite is needed to allow the initial image to incorpore new elements : for example, let's say the mage cast the spell alone in his sanctum, with the extra-magnitudes, the spell will adapt the image if the mage moves a book in the room or correct his clothes. But if something new appears, like his familiar entering the room, the muto requisite allow the image to change to accomodate the new element.
So it would be : Cr(Mu)Im base 1 (Create an image that affects a single sense) + 1 (Requisite : Muto) + 1 changing image + 1 moved image matches changes
Note that without an Ignem requisite the magical mirror cannot reflect light