Hello. I am for lack of a better word, a newbie, when it comes to VFX. I'm also disadvantaged as I am an economics major, and have never studied filmmaking in any capacity. However, I have for the past 1 1/2 years, studied cinematography from any source possible. (mostly books). I understand the basic concept of chroma key but I am confused about a couple of things, that I was hoping could be cleared up on this forum.
1) When should I use Blue vs. Green in a chroma keying situation. I heard something about blue being further away from red on a vectorscope.
2) When the desired shot is a focus pull to an element that will be in the matte, is it better to shoot the footage with a focus pull, or save it for post. Does the lens create a blur around the edge at some point in the transition, making it difficult for an accurate key?
3) In many behind the scenes, where I see professional VFX being done, I notice these green x's of tape on the background. I haven't found any literature online about them. My guess is that they are reference marks for the compositors. Could anyone validate this for me?
4) Are there any professional methods to pulling the "perfect" key? My understanding comes from having the actor as far away as possible from the blue or green, because the further away, the less spill. Also having the background and the subject separately lit. From my understanding it is usually common practice (depending on the nature of the intended composite) to light the subject in tungsten, or anything with a 3200K colour (yes, i'm canadian) temperature, and the background with fluorescent, or green filtered light (in this case assuming the chromakey screen is green). This allows the colours to be more separated in the vectorscope allowing for a cleaner key. Are there any other things I would need to know in order to pull a "professional" key.
4b) I guess what I want to know in general, is what separates your average chromakey work from the absolutely astounding?
This is my first post, and I feel it warranted a small intro. Sorry for it's length.
Thanks in advance,
Michael Sousa