Continuity mistake: In the opening scene, Novak is walking down a corridor with a woman, and when she says, "Where did you get that scar on your chin? " Novak puts his hand to his mouth to cover it when he coughs, but in the shot from the security camera and normal view his hand is not at his mouth. (00:01:25)
Continuity mistake: At the beginning, when Blade is chasing the vampires, in one shot two of the vampires are on the right, then one is on the left. Also, when Blade shoots them he runs past the exploding corpses, but in the next shot he's running past them again. (00:05:05)
Continuity mistake: When the 3 vampires slide down the fire escape there are 3 motorcycles. When the third vampire lands the 3rd motorcycle is gone. (00:05:45 - 00:06:22)
Continuity mistake: When Blade's giving Whistler an injection, in one shot he has just his left hand on the back of Whistler's head; in the next shot, he has both hands there. (00:13:35)
Continuity mistake: Close to the beginning of the film, when Nyssa and the other vampire come to offer a deal, Blade says "take off your masks", watch Nyssa, in one shot she takes the mask off with her left hand, then it switches to the right hand. (00:21:55)
Continuity mistake: When we first see Novak in the head vampires's house on the computer, the image we see is not from a security camera perspective. (00:25:25)
Continuity mistake: When Blade meets the Bloodpack for the first time, Reinhardt (Ron Perlman) tries to instigate him, and the rest of the Bloodpack draw their weapons on him. When Nyssa motions for them to put their weapons away, we see a shot of the entire group putting their weapons down. Snowman(Donnie Yen) had partially drawn his sword, and resheathes it. Immediately afterwards it shows him doing this again. (00:31:50)
Continuity mistake: Just before the blood pack enter the house of pain, Scud shows Blade the pneumatic wristblades but doesn't actually give them to Blade. Blade can only be seen wearing them when he uses them on Nomak, after which they are gone again. I know they were retractable, but if you look even when retracted they should still have been visible. (00:34:29)
Continuity mistake: In the scene where Blade and the Bloodpack go to the club to find reapers, there is a clip where Lighthammer and the girl go into an area by themselves. When it shows the two, the girl has a blue light filter on her gun, but when cuts back to her, there isn't any filter on it. (00:40:02)
Continuity mistake: When Scud is in his van looking to investigate a noise, you see a donut and a cigarette in his right hand, but when he turns on the lights, there is only a cigarette in his hand. (00:41:42)
Continuity mistake: In the house of pain scene, when one of the members of the blood pack, the one with the swords, stabs a reaper, he steps away and puts his hand on his other sword, in the following shot, he doesn't have his hand on the sword. (00:45:35)
Continuity mistake: In the House of Pain sequence, Chupa is firing his machine gun at a Reaper who is fleeing across a balcony. As the shot cuts between different angles, Chupa's over-the shoulder angle indicates the Reaper has run over fifty feet. However, the balcony view where the Reaper runs directly towards the camera is the same section of balcony multiple times. Two female extras cower in terror against the wall several times before finally being killed by stray bullets. (00:46:16)
Continuity mistake: In the middle of the film when the Bloodpack gear up ready to go out and into the sewers to find the reapers. Blade and Nyssa are talking at a table, Whistler shouts "hey Blade, give me a hand". In this shot we see Nyssa looking at Blade, but in the following shot she is now looking down and away from Blade. (01:04:35)
Continuity mistake: When they are underground and Reinhardt is about to shoot a load of reapers, he is standing with his back to the side of a small tunnel, but in the following shot, he is right in the center of the small tunnel. (01:12:45)
Continuity mistake: At the end of the film when Reinhardt and Whistler are in a room together, Reinhardt turns and looks at the monitors and mouths "what the f**k?" he turns his head to the side, yet in the following shot his body is side on, and he is looking right at Whistler ready for the punch. (01:27:00)
Continuity mistake: When Whistler shoots the lawyer from under the floor, you can see that the bullets go in at a diagonal angle, (up and to the left), but Whistler is straight under him. Therefore, the bullets would have to go straight up through the lawyer. (01:31:00)
Continuity mistake: At the end when Reinhardt and Blade face off, Blade grabs hold of the sword, and in one particular shot the sword bends, yet in the following shot, it is straight. (01:33:15)
Continuity mistake: Just after Scud gets blown up, Reinhardt's face has no blood on it. Yet when he walks out of the room with Whistler, his face is covered in blood.
Continuity mistake: After Nomak rips into Damaskinos's neck, Damaskinos backs up with no blood on his face, but in the next shot, his mouth is suddenly covered in blood and he is spitting up blood rapidly from his mouth.
Continuity mistake: During the scene where Damaskinos is talking to his lawyer, there is a lot of the jello-like blood substance on his plate. However, when he gets up to go to the pool of blood, there's nothing on the plate.
Answer: In Blade I we saw that with sunscreen and the avoidance of direct exposure Deacon Frost and his lackeys could go out by day. The reapers are probably two or three times more sensitive than normal vampires so the exposure was probably not long or direct enough to kill the regular vampires.