How do they film continuous blood pooling?

Question

I have seen in American Sniper, Dead-7 and Carrie that when someone is killed, they are laying on the ground with blood leaking out of their back or somewhere else on the body. The puddle continuously grows with few signs of slowing down. This is obviously not CGI because it is a real liquid (may not be real blood as that would spark an emergency in real life). I have seen in American Sniper that when the protagonist kills yet another enemy, they are filmed hitting the ground and blood starts pooling around their body. In Carrie: In the dance room where Carrie sets her powers loose and kills a lot of teenagers in the process, there are a few that hit the ground with blood pooling under their bodies. Sometimes they would be on their side with blood coming out. In Dead 7: Kimono and the other six killed lots of zombies. Some of the six were killed in the process as well before they came to Apocalypta to kill her. They were filmed hitting the ground dead with blood pooling around them.I am not sure how they film this as they are wearing thin shirts for these scenes, and not only that, but the characters also have blood (obviously fake) only just dripping out of the side of their mouths (an indicator they have a ruptured and wounded stomach or lung (in this case the blood would be pink and frothy). What is the film technique that allows this to happen?

Answer 1

bag or bags of blood with a hole in it....just like a person with a hole. Leaks out at whatever rate the size of the hole is. My guess is that's a shot that's done 6, 7, 8, 11, 16 times until it looks perfect.

And remember, right outside of the frame, where you can't see....is a crew of 60 people helping what you see happen look authentic.