"Vampires are ostensibly vulnerable to sunlight (or specifically the UV radiation thereof). However, in scenes lit by nothing but natural sunlight, they're repeatedly left completely unharmed. The deciding factor seems to be whether they have line-of-sight to the sun itself, as anything short of that appears to have no effect at all. Apparently, light in this world doesn't bounce, but just stops whenever it strikes anything solid enough (but can still somehow illuminate the rest of an enclosed space)."
A while back I bought an electronic UV meter online to see if my home windows could block UV. The meter gave a positive reading when turned into the sun, but a reading of 0 when put right next to LED bulbs, so I know that it worked. I tried pointing it at objects lit by the sun, but even outside at Noon on bright days, it never gave a reading above 0 (I never tried pointing it at a reflection of the sun in a mirror, though). Clearly, diffusely reflected UV light from the sun is far less powerful than direct UV light from the sun. Visible light works similarly, which is why you aren't blinded if you open your eyes outside during the day but you do risk going blind if you look directly in the sun.
Regarding this:
"Vampires are ostensibly vulnerable to sunlight (or specifically the UV radiation thereof). However, in scenes lit by nothing but natural sunlight, they're repeatedly left completely unharmed. The deciding factor seems to be whether they have line-of-sight to the sun itself, as anything short of that appears to have no effect at all. Apparently, light in this world doesn't bounce, but just stops whenever it strikes anything solid enough (but can still somehow illuminate the rest of an enclosed space)."
A while back I bought an electronic UV meter online to see if my home windows could block UV. The meter gave a positive reading when turned into the sun, but a reading of 0 when put right next to LED bulbs, so I know that it worked. I tried pointing it at objects lit by the sun, but even outside at Noon on bright days, it never gave a reading above 0 (I never tried pointing it at a reflection of the sun in a mirror, though). Clearly, diffusely reflected UV light from the sun is far less powerful than direct UV light from the sun. Visible light works similarly, which is why you aren't blinded if you open your eyes outside during the day but you do risk going blind if you look directly in the sun.
Edited by INH5