Dunno, I think it is more about bump - since the surface beneath a thin film of blood is not perfectly regular, the layer of blood itself would not be perfectly flat, so imo some bump is mandatory.  There is some procedural bump in my shader that looks more like a countour map, so it isn't really great for simulating blood perfectly but the color and specularity, I think they're okay.  A bit cinematic though, it looks VERY wet (probably more than it should if it were real blood).

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