Theory 57/Blushing/Ratio lens
Intensity Is Inflow Against Return
The claim
Blush intensity is set by the ratio of arterial inflow to venous return, so a blush fades when venous drainage improves rather than when inflow stops.
01Mechanism
Colour reflects blood pooling in the dermis; the balance of inflow and outflow determines how much accumulates.
02Prediction
Intensity should track the ratio.
03Refutation
Intensity tracking inflow alone would remove drainage.