How do you make greenscreen blood?

Are you shooting a scene where a greenscreen is attacked and bleeds? Is it a war between practical FX artists and CGI artists?
(kidding)

We're not exactly sure what you're asking but normal blood color should be very good for a greenscreen shot, unless it is green alien blood or something.
 
The only thing I can think you mean is for blood spurts and bursts. You don't need to greenscreen that. In fact, that may be the worst route you could take.

All you need it a high contrast practical effect you can later use as a Luma Matte. A white background with black paint, or a black background with white paint would be great. Which to use would depend on your lighting capabilities, with the black background being easier with less than great lighting.

Then it's all in the hands of your compositor to attach a color for the Mate to push, and other things like Specularity. I'de shoot with a higher shutter speed than normal, since adding motion blur is eaiser then removing it, and as high a FPS as you can.
 
I wanted to make fake blood and use food coloring so when i edit the blood on FCP i could use the greenscreen effect to make the color of the blood bright.
 
You wouldn't want to do that.
When you key out footage, you are cutting a hole out of it. You would lose the properties of the material. Therefore it wouldn't look like a liquid, or a stain, it would just be brgiht red patch on a body, or shirt. no depth, no shine.

If you want your blood to pop, make an adjustment layer, and mask it so it only affects the area that has the blood. Then you can do all the tweaking you want and it will still have its original form.
 
Yes, what I said stands for tha clip. mask out the area of the blood on an adjustment layer (After Effects) and then play around with the color/hue/sat ect..
 
See bone hand on my website. I did using the dropper in threeway color correct in FCP I find that no matter what, in all my films I have to adjust the color of blood in post. I lean towards brighter red when shooting now because it's so easy to take darker / less saturated in post, but it's harder to make redder and shinier. If there's a lot of red in your shot it will effect all of it, and maybe even skin tones, in that case you have to do the mask like drk3p says.
 
NASDAQSUPERSTAR said:
How do you make greenscreen blood? I am shooting a war scene and I was looking for the ingredients to make greenscreen blood.
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I never get these vague questions. The more specific your question is the more specific your answer will be.

Short answer is: You cant.


Having said that...

The det films blood splat shots probably won't do you any good. They were shot on lo res green screen (last I checked) which is an issue and unless you also shoot at close to the same angle as the original splat was shot, static/locked down cam also, in an effort to match the prespective, then your really screwed.

Even if it all matches, and your shooting lo res 480p, and if you have a low budget look to it, you might be okay. Under close inspection though (frame by frame) it'll look less than ideal.

Practicles if possible would, imo , be the way to go, with some post work to remove wires and tape and what not. Barring that, if it has to be green screened sepereately and added in post, well, honestly, I wouldn't waste my time with it.

CG is the other route, but you'll need somone with some experience
to do it right, and don't expect it to be easy for them and assume they'll do it for free.

Check out the Jackie Chan interviews on youtube, if they're still there, on how they handled the low budget blood hits/slashes using realtime practicles and shifting body movements to hide some things from the camera. It's all in the choreography with those shots. Very detailed and effective directing.

I wouldn't touch green screen blood with a ten foot pole. Besides, the edges of the blood will be all blurred. It just never looks right unless, like I say, it's a low budget do-it-yourself type of short and you have no worries if it's a bit off. In that case, try it. I've done it, it did the job but it was what it was. Depends on what quality your after.

//not to sound confusing, by "green screen blood", I mean, red blood shot against a green screen.
 
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