Hmm. As I understand holography, it's done by illuminating the target object with a laser, and directing half of the original laser beam directly at a photographic plate while the other half bounces off the target object and from there on to the same plate, leading to an interference effect.

I think that given my model as specified above, I would have to say that it would make no difference if the target object is a vampire. The R-photons going through the vampire would miss the plate, and wouldn't affect it even if they reached it; the S-photons bouncing off would hit the plate and affect it as normal, since the plate changes state in response to photons and hence clearly qualifies as a sensor. Hence, you can take holograms of vampires in exactly the normal way.