[Ian Maclean]

It is not.
Don’t use blue light, regardless of the source –whether it be fluorescent or tungsten — on your greenscreen when you’re using ‘amber’ light on your subject.

Please explain what a blue tungsten source light is. My impression is that you are in contradiction.

[Ian Maclean]

Hi Mark

Thanks for the helpful and considered response. A few things:

-I’ve already been informed that I should cut my key in my compositor anyway, and we are shooting greenscreen, so compositing will be part of the workflow one way or the other, so I’m not sure how much additional work it will really take. My camera’s chips generate about 1400 x 810 pixels, so rotating on it’s side makes for a potential vertical resolution increase of more than 40%, nothing to sneeze at and only costing unused horizontal space. And remember that increased resolution is in 4:2:2, so in theory there is good payoff for cutting the key.

-The gels I’ve seen, and on recommendations from The Cow, purchased, come in a variety of densities the lightest of which I can’t see ‘significantly’ reducing the output.

-I also haven’t had anyone address what seems to me a potentially common dilemna for entry level / low budget shooters: those using tungsten for key and backlight, and fluorescent for backdrop. A light green gel would remove any potential for blue light spilling on to the subject. Right? Rest assured, I will be diligent in preventing my backlights from spilling, but this is a potential fix to a potential problem, is it not?

-Greenscreen is all about color, supposedly. And the best way to enhance an object’s color is to hit it with light of the same color. I’m not sure a light green gel will require additional light. I should be overpowered anyway, and I’m just subtracting light I don’t want or need in the first place. Reducing white spectrum light from bouncing off the greenscreen should improve the color going into the camera. The nice part is that the gels were cheap, and I can fine tune with the camera’s built in waveform, and see what works best. I have to say I like the peace of mind of not worrying about blue wash contaminating my subject.

-I’m not sure where you get the idea there would be different shades of green or uneven lighting. I have two identical lights, and each would have identical gels on them, they’d be placed symmetrically on the screen, and my key light has eggcrates and would be placed to avoid the backdrop. I’m busting my ass to get this to work in an environment with serious limitations of which I’m aware and recognize.

-I researched and ruled out a reflecmedia type system a while back. Grey halo seems an issue, as does the eyelight (I may want my subject in glasses), and the stability / quality of the lightring mount. Getting the lightring as close to the lens as possible is somewhat prohibited by a non spherical lens, and alignment is crucial and I’m not confident in plastic mounts for this quality. The cost is high, not enough people / companies are looking in to putting the green light behind the subject’s head, etc, etc. I think the technology for this will be much more mature / proven five years down the road. Maybe by then I’ll have an EX3 or HPX300, and be able to put a wide selection of spherical lenses on them. And afford the cloth which will be sold less expensively from China or India.

-Actually, the idea of lighting the backdrop from behind is very appealing. My studio has natural places for such lights, and my material is simply paper. Even if too thick to be practical, potent gelled lights behind the right material might be a perfect way to go. Thanks very much for the suggestion.

[Ian Maclean]

-“…You’re spending too much time THINKING about green screen and too little time actually doing it.”

Well, it’s hard to ‘do it’ when you don’t have any tools. I like THINKING about how I’m going to film something, and what tools I need before I actually purchase them. I call that RESEARCH.

-“It would have been far more useful for you to have filled us in on all the details of your project from the very beginning — especially the information you shared in the last few emails — instead of the piecemeal approach you took (…starting wih the odd email about covering your lights with green fabric).”

Did you bother reading the first three sentences of this posting? What word didn’t you understand? Indeed, there have been complaints about postings that are too vague, or poorly researched, and a call for topics with specific questions. I have tried to be specific, gracious, and thankful for valuable information, especially when it corrects inaccurate facts.

I think it would be far more useful for you to have followed Creative Cow guidelines:
“…our primary task as the owners and management of Creative COW is providing an atmosphere conducive to generating: …A safe environment for students and other inexperienced individuals to enter discussions, whether presenting questions or answers.”

-“I still don’t think you’re quite understanding the essential elements of setting up a workable key.”

You think wrong. I’m not stupid, just inexperienced. I understand everything you’re saying. And understood it before I saw your post. I knew I’d be working in a limited environment, and it was a prime consideration in my purchase of a Panasonic HPX170 (“The lens has a new focal length range, 3.9 to 51mm. In practical terms, the HVX200A is wider than the HVX200, and the HPX170 is wider than both of them”). That’s the 35mm equivalent of a 28mm lens, and in my second sentence I clearly said I was shooting “mostly medium shots of a single subject…” Short of that subject being LeBron James singing Jesus Christ Superstar, I’m hoping I’ll be able to manage.

I also understand the how the software works, and how the color data is captured, and plan on recording HD SDI out of the HPX170 straight into pro res 422, (that’s 4:2:2, progressive [yes, I’m aware it’s only 8 bits embedded in a 10-bit word]). No compression. I am ALL about as workable a key as I can get, and with this added color data I feel I might have a little lattitude to lower the IRE a bit to reduce green spill. Naturally, I’ll need to experiment a bit, but sometimes the technology, in it’s recent advancements, can come first. Especially in comparison to even the best hardware of only a few years ago.

Sadly, your forum software won’t allow for stickies, or even FAQ’s unique to each specific forum. I am always thinking of saving the next guy some time, so I’m going to repost your otherwise excellent summary under this new topic title: “essential elements of setting up a workable key.” There are a lot of inexperienced people who are going to be coming to Creative Cow, and this may make those comments easier to find.

-“Unfortunately, I feel it won’t be understood”

Perhaps save your condescension for when it’s justified and try to keep the tone of this forum a bit more friendly. While you’re at it, maybe you could stick to the topic (literally) by answering the direct, simple, technical questions being posted to the Cow. I’m still waiting on these:

-Not sure exactly what height to place the [backdrop] lights. Slightly above, or below the height of the subject?

-The fluorescents are 5500k. I like the idea of inexpensive ($8 / 21″x24″) green gels both for supersaturating the screen and for filtering out the daylight color in my small [tungsten-lit] studio. The greener the light hitting the green paper backdrop, the less I’ll have to use (and these lights give the option of how many of the 5 bulbs to use at any time), the more options in intensity range I’ll have lighting the talent. I think this reasoning is sound, but do let me know if not.

[Ian Maclean]

Michael, thanks very much for the info. I’m going to start a new thread and repost your entry.

Re: Portrait mode: Mark, I wanted the cleanest high def footage possible, but was worried about the width of my greenscreen, my 16:9 camera image ratio, and the small room making the camera, talent, and backdrop all closer to each other than ideal.

It was suggested to me that if I turned the camera on its side, my medium shot of seated talent would get a significant boost of pixels for keying (1280 vertical pixels), and eliminate the widescreen dead space. I’ll be using a compositor and outputing to 720p, so the larger than necessary size of the subject footage will do nothing but help the composited image quality. It’s a win-win. I’m not sure what digital signage you’re referring to, but that was my motive, and it seems a worthy setup. I’ll post results in Cinematography as soon as I’ve run some tests, thanks for the suggestion.

[Ian Maclean]

Mark, thanks much for very useful info. Especially for anyone such as myself who hasn’t used them before. I’m kind of assuming that those rules are for a softbox with the max rated lamp inside. If you have a variety of lower intensity lamps, I’m also assuming that would shorten the minimum distance, useful if you’re working in a small room. Right? Again, thanks.

[Ian Maclean]

I think also perhaps I didn’t emphasize enough that I’m locking my camera down sideways, and will essentially be shooting in ‘Portrait’ rather than ‘landscape’ mode. 9:16, in other words, and tuning the camera lens / distance to only need effective greenscreen a little wider than a medium shot of seated talent. I’m hoping that’s a limited backdrop a little easier to light than a full wall.

[Ian Maclean]

Thanks for that. I went round and round on my options, and Boy Howdy are you dead-on about the cost of the Lowel egg crates. However, I couldn’t get around the benefits of really nice, high CRI, controllable light and so bit the bullet and blew half my lighting budget on the Rifa 88 and eggcrate (40 degree).

I really love the modular design, and that if I have any future need to, I can have a big pretty softbox that will run of a huge range of bulbs, even off a car cigarette lighter, with the purchase of a few additional parts. Very cool, and I’m hoping I really like the light from the big diffuser.

[Ian Maclean]

Many thanks for the advice. As something tells me there will others looking for info on setting up greenscreen on a budget, I’m going to share some of the information I’ve come across.

I only ordered my lights yesterday, have no direct experience with greenscreen, and am trying to squeeze every penny by making smart choices.

I think that, like many, I’ve ended up with Fluorescents to light the backdrop and tungsten halogens for my key and backlights (blew most of my budget on Lowel Rifa 88 [w 40 degree egg crate] softbox for key, reflectors for fill, Lowel Prolite for backlight, both with a good range of lamps / bulbs and dimmers [for mild dimming if needed]). The fluorescents are 5500k. I like the idea of inexpensive ($8 / 21″x24″) green gels both for supersaturating the screen and for filtering out the daylight color in my small studio. The greener the light hitting the green paper backdrop, the less I’ll have to use (and these lights give the option of how many of the 5 bulbs to use at any time), the more options in intensity range I’ll have lighting the talent. I think this reasoning is sound, but do let me know if not.

I’ve had conflicting advice about fluorescent bulbs and how much (or any) diffusion they need if they are getting bounced off a backdrop. I think I’ll just need to experiment, but maybe if I had it to do over again I’d buy long tube fluorescents to light the backdrop, as Bill Davis recommends. Oh well. I can always rig some kind of soft diffusion / softbox if indeed these screw-in bulbs need it.

I guess the rule for those new to lighting, that really doesn’t get said clearly or often enough, is that “The bigger the surface area of the key, the softer the results will be.”

[Ian Maclean]

Right you are on the 650, thanks. And thanks again to this list and the expert advice.

See new post on backdrop.

[Ian Maclean]

see new post. Thanks.