Quote Originally Posted by YianKutku View Post
I'm still not entirely sure if the particular concoction in that ALC questline (50-60, if anyone was wondering) showed the actual objective colour of a person's soul, or if it shows a colour that happened to be unique to each person.

For example, using the dust, the colour of the WoL's soul is "blue". I don't know if that's just the colour as shown by the dust itself, or if Hythlodaeus would agree "yes, that soul colour is that exact shade of blue". In other words, whether the dust is fingerprinting (showing the actual form of the mark) or Luminol (showing the presence of the mark, but using its own output).
I want to say the other person's aether was said to be red. The same color that matched the book or was it the ink used by the killer. So it would be fingerprints as in that questline is where we learn that everyone has their own unique aether color.