Leigh B. , Nov 26, 2010; 12:56 a.m.
Yellow is "minus" blue.
White light has red, green, and blue components. Yellow is red + green, i.e. white minus blue.
If you turn up both yellow and blue you'll get white (perhaps tinted, depending on the ratio of the colors and the accuracy of the filters).
Magenta is red + blue, thus white minus green.
Since I don't know what kind of image you envision, I can't answer your question.