 Without strength, one can never fathom taking on the other six virtues.The most striking color in the work is obviously Fortitude's red robe, which is so elegantly draped off one shoulder and laid across her lap.Tempera paint is incapable of producing the hard and cutting edges that occur in oil painting, and this because of a very remarkable property, namely, the comparative transparency of even opaque colors when mixed with yolk of egg.