An example of minor magical focus given in Arm5, p.46, is "a particular color" -- say, red. I'm trying to gauge the applicability of the focus.
Clearly, it applies when changing stuff from blue to red or from red to blue.
But would it help a magus bind a red familiar?
Would it help the magus when creating a tower of red porphyry?
Would it help the magus make a red-headed girl fall in love with him?
Would it help cast a MuVi effect on a spell whose sigil was the colour red?
Would it help the magus when casting an InMe, T:Vision spell that makes people who bear him a grudge appear red to his sight?
Nice one. Never looked at it, nor have any of my players.
To me, the familiar is red in essential nature, like a (don't take this for racism please, just as a generalization) moor will be brown and a brit white-ish. So yes.
The red in the porphyry is just cosmetic, so no.
Red headed yes. If you consider that red and not orange, that is.
Yes on the sigil. The sigil is part of the essential nature of the spell (only muto can change it, but you cannot destroy it IIRC; might be wrong here though).
Cosmetic red in the InMe spell (like the vapor in frozen breath) so no.
But we tend to play fast and loose with rules, so more hard rules people might prove my theories wrong
Except that the minor focus is stated in the Art of Imaginem. And all of the stuff you are proposing fall outside of Imaginem, so they would not fall within the perview of the focus.
What would work is:
Create an illusion where all of the image is in different hues of red
Modify the species of a person so that their hair looks red
etc.
Basically, anything that involves Imaginem and the color red. Yes, that makes it of very limited usefulness, unless the player is quite imaginative.
Hmm, I tend to agree with you folks. Most of the activities I proposed as examples would not benefit from the focus, with one or possibly two exceptions.
In particular, I think that turning red (even if only in the perception of the caster) someone who is angry would fall within the focus. I also think that, although the focus should not be applicable to every red familiar, it should be applicable to any familiar for which red was sufficiently central to its identity to deserve Imaginem as a bond Art. The closest example that comes to me would be the murex, the only source of the purple-dye of antiquity (ok, purple is not exactly red, but you get my point).
