'Scarlet,' as in Genesis 38:28, signifies spiritual good.

In Isaiah 1:18, this signifies truth derived from good, or truth from a celestial origin, such as is the truth of the Word in its literal and natural sense

'Scarlet,' in Revelation 17:3, signifies truth from a heavenly origin, such as is the truth of the Word in the sense of the letter or natural sense, which is meant by what is holy in it. 

(Odkazy: Apocalypse Explained 67)

3485. The representations that occur in the next life are appearances. But they are living representations because they come from the light of life. The light of life is Divine Wisdom, which is received from the Lord alone. Consequently all things that come into being from that light, unlike those from the light of the world, are real. For this reason people in the next life have said several times that the things they behold in that world are real, whereas those that man beholds are by contrast not real. The reason for this is that the former are living and so have a direct influence on their life, whereas the latter are not living and so have no direct influence on their life, except insofar as things with them belonging to the light of the world join themselves appropriately and by correspondence to those belonging to the light of heaven. From all these considerations it now becomes clear what representations are and what correspondences are.