Question for shooting for keying out colors

[Logan Triplett]

So i'm shooting for my final cinematography project next weekend for college. The group that I'm shooting with wants to have shots where everything is black and white except for this paint that some guy is painting with.

 

I was thinking that we could have all of the paints green screen green, and just key out everything. Next I would take the keyed out image and convert it to monochromatic, next I would overlay that on top of the original image, rendering the specific colors visible. Then I would change hue of the green to get the color I wanted.

 

Would this work?

 

I'm shooting with hvx200a and a letus. If done right the only kink I am seeing is that I would be restricted to one specific color. Is there anyway to work around this? Could I use two specific different colors to key? like green and the red screen?

 

Sorry if this sounds confusing, I'm in class trying to listen at the same time ha.

 

Please email me if you have any input at redmagicmarker@hotmail.com

 

Thanks!

 

Logan

[Chris Keth]

You could pull different keys like you are suggesting. Just remember that cleaning up those mattes will get very tiresome and time consuming if you go over a couple of colors because the more colors you try to key with, there is a greater likelihood of those colors also being found in your talent, wardrobe, set, etc. Also, places where the two colors of paint mix will have to be added-to or subtracted-from to the matte by hand.

[Logan Triplett]

yeah thats what i was thinking. I'm going to try to work around things by having nothing interact with the frame, or doing some extreme close ups, and then only do a minimum of the green screened shots.

[Tom Hepburn]

If it were me, and it's not, I would consider doing this in post. However, that may not be what your instructor is trying to teach you with this assignment. I would check first if this is an option.

 

In AfterEffects there is a plug in called leave color. It takes a little tweaking, like everything seems to need in post, but with some masking it should work nicely. Of course I would do a test first. If for example you want to keep the red paint red, you would want to make sure that there is no other Red in the footage. Mostly cyan would probably be best. That would save a lot of masking later.

 

Thought I'd mention it.

 

Tom

[Jim Hyslop]

You could pull different keys like you are suggesting. Just remember that cleaning up those mattes will get very tiresome and time consuming if you go over a couple of colors because the more colors you try to key with, there is a greater likelihood of those colors also being found in your talent, wardrobe, set, etc. Also, places where the two colors of paint mix will have to be added-to or subtracted-from to the matte by hand.

A garbage matte would help a lot - create the matte the same size as the painting area. If necessary you could rotoscope a matte around the actor, although that's very tedious and time-consuming (been there, done that, prefer not to do it again if I don't have to).

 

--

Jim