Talk:Transillumination

While it is true that hemoglobin absorbs green and let's red through, that is not the only (or main?) reason tissue appears pink. For example, caucasian tissue devoid of blood would still be pink under white light transillumination because of its light scattering properties. The red portion of the spectrum experiences significantly less loss due to scattering than the blue end. This fact is used to great advantage in estimating the depth of tumors with fluorescent tags using very sensitive cameras. The increased scattering of shorter wavelengths implies fuzzier images but it provides useful depth information to compare the different wavelengths. A company called Xenogen (acquired by Caliper Life Sciences) produced small animal imaging systems based on this technique.