John Keates
03-26-2008, 05:40 PM
I was wondering why veins can look blue even though blood is always red and I found this paper:
http://www.imt.liu.se/edu/courses/TBMT36/pdf/blue.pdf
I'm not a mathematician so I found it a bit hard to understand but I think the basic jist is that de-oxiginated blood is a deeper red and absorbs more light than oxiginated blood. This means that it absorbs more of the light that is scattering around in the skin. The light that scatters the furthest is red light and if the vein is quite deep, it absorbs this red light. The result is that the vein produces a relatively blue area and, although it isn't blue, it looks that way because it is bluer than the surrounding area.
People might like to check up on my interpretation to make sure I got that right.
Anyway, I thought that might be interesting for some people.
http://www.imt.liu.se/edu/courses/TBMT36/pdf/blue.pdf
I'm not a mathematician so I found it a bit hard to understand but I think the basic jist is that de-oxiginated blood is a deeper red and absorbs more light than oxiginated blood. This means that it absorbs more of the light that is scattering around in the skin. The light that scatters the furthest is red light and if the vein is quite deep, it absorbs this red light. The result is that the vein produces a relatively blue area and, although it isn't blue, it looks that way because it is bluer than the surrounding area.
People might like to check up on my interpretation to make sure I got that right.
Anyway, I thought that might be interesting for some people.