Your magic is obvious, surrounded by a glowing nimbus of light, accompanied by weird sounds, or associated with other FX that give you away and point to the magic tradition you are using. This is not a problem for direct, physical magic like fireballs, but is a great hindrance to detection and illusion magic. But it never wholly spoils the magic; an obvious illusion shows its presence by strange phenomena, but these phenomena do not point out the illusion, only the presence of magic and the tradition of the sorcerer.