Pull Process/Green Screen with Kodak Vision 3 500T 7219
Posted 15 February 2011 - 08:39 PM
I'm shooting a short student film this weekend on Kodak's Vision 3 500T 7219 Super 16mm stock and I wanted to know if anyone had any suggestions for not only shooting the stock in regards to keying/green screen, in addition to pulling the film's ISO. As of now, all the green screen work is taking place in a well lit, green screen cyclorama sound stage. My logic behind pulling the film is to reduce any film grain to make the VFX team's job easier. As of now, I'm planning on pulling one stop and making the films effective ISO 250, though if pre-rigging goes well and we have more time to finess I might even bring it down two stops to 125.
Do you folks have any suggestions/concerns that I should take into consideration before shooting this weekend? Anything you have to offer would be great.
Posted 16 February 2011 - 01:51 AM
Posted 16 February 2011 - 07:23 PM
Thanks for the $0.02. I appreciate it. You don't happen to have any stills, do you?
Posted 16 February 2011 - 07:53 PM
And before I get labelled as a 500T-basher, I'm going to back this one up with an ASC member's opinion on the subject. MOre quotes available upon request:
"Vision 2 500T (5218), a remarkably fine-grain high speed film, as one would expect is still slightly grainier than the lower speeed films. It is not ideal for blue- and green-screen work."
Many productions working with 16mm choose to up to 35mm for SFX work. Many 35mm productions opt for 8-perf. Vistavision cameras. This is all in an attempt to cut down on grain and get clean subject to matte separation.
Make sure you light your bg to the same T-stop or one stop under. Be careful to meter correctly. The recommended method is still to do it by eye, using either a green or blue filter to adjust the brightness of a white card illuminated to key to the same brightness (or minus one stop) as the bg appears, visually.
Something to do with the specific colors means that a meter own't be the most accurate method. It's looking at visual brightness across the spectrum, not designed for a narrow wavelength blue or green screen.
Don't bother pulling two stops, I'd probably just try for one. Overexposure gives scanners trouble. Don't get "bulletproof" negatives to give to the telecine house.
I wish I had consulted with you before you purchased film. Can you trade a can with someone? Get ahold of some '12, anything 200-speed or slower.
Go to a film dealer, pay them some money and trade. Better yet, get some 35mm. Of course, not everyone has a friend with an Arri and a Mitchell he can just borrow.
But you'll really do yourself a favor NOT shooting 500T 16mm. Short of 8mm film, this is the absolute worst combination I can think of for this setup. Only stock I can think of worse would be Expression or Reala 500D.
Edited by K Borowski, 16 February 2011 - 07:55 PM.
Posted 16 February 2011 - 08:36 PM
And, if you don't have '12 or '13 stocks, then shoot '19 but don't pull, I'd just over expose rating it at something like 320 (test as I might do 250) and hope you have a good compositor.
Posted 16 February 2011 - 10:12 PM
It probably only costs more money spent at the film lab, digitally. Software is much more adept than photochemical methods at isolating color.
Another tidbit of information: Vision2 (and 3?) stocks instead of producing a black matte line when used for composites, are instead prone to a RED line. Even digitally this shows up. I would assume Kodak isn't worried at all about anyone doing an optical composite anymore.
Even digitally, though, if you get a bad matte line, it can be partially obscured digitally, but only at grat expense.
Due to more even speeds across color layers, my references indicate that daylight stock balanced with HMI lighting gives a minimum of matte lines, due to relatively equal speed across layers.
What I've seen recommended is actually the use of a REDSCREEN with daylight balanced stocks, due to that layer being finest grained.
Posted 16 February 2011 - 11:32 PM
Posted 17 February 2011 - 08:22 AM
Keep in mind I've never SHOT mattework, just dealt with keying it. I've been reading up on it extensively this past month, and helping someone key it from another non-optimal format, HDV. So I've been looking at the same issues, more that what he has been using is for traditional film work that the SOFTWARE was originally designed to work with.
It's more what the post houses are set up for than what is actually best with cameras and equipment that people seem to be shooting. IDK, is there a deal on green paint?
I'm on the fence now as to WHAT I'd shoot. I'd have gone with 100T before, and still can, but pretty soon that's not going to be an option; thanks Kodak. So it'd be a tossup between 50D, F64, or one of the 200T stocks.
From what I gather though, new stocks can be WORSE with Red fringe in the Vision line. I'm looking at all of this in terms of clean matting, not fine grain. Don't have the ASC manual sitting in front of me, but there is a lot of interesting technical information spread across two or three articles, all of which I have bookmarked.
Doesn't help that the tests I've seen for matte work all are several years out of date. . . Anyone see any articles online or in one of the magazines testing the new V2/V3 stocks. What about Fuji stocks? I'm sure a lot of the stigma I've seen towards shooting them is based on similarly out-of-date information from the optical printer days.
Posted 18 February 2011 - 09:22 AM
Thank you for your advice and technical concerns. Obviously, this is all stuff I've never even thought about before and i appreciate the fact that you're trying to pass on your knowledge of the subject onto a humble student like myself.
However, because of these concerns and those of our production company's to afford the post-processing of pulling the film, as well as the fact that we can't afford to get a different stock in enough time or paint the sound stage a different color, we have opted to shoot all the green screen shots on digital with the Canon 7D. Though I have my own concerns about this line of cameras, we just don't don't want to risk the amount of grain and problems we might see once we get the dailies back. We have a very limited budget, as well as man power and technical prowess in the post department and we don't want to risk a faulty final product.
Thanks again for all your help. I'll be sure to let you know how the shoot goes.
Posted 18 February 2011 - 09:58 AM
Posted 18 February 2011 - 12:10 PM
Don't think digital is just going to be "easy" to fix. With a "digital" camera, you're dealing with an analog CMOS or CCD sensor, an electronic device. With film you're dealing with a latent image that has to be chemically developed into black metalic silver or silver replaced with dye clouds.
I'd shoot a quick test with both, and see which you like better, with no tests comparing the two in front of me The same advice holds true, though: You need to get the visual reflectance of a white card and the screen to be lit to the same reflectance, looking through a filter matching either blue or green screen to pull a clean matte in the software.
I'd look around for articles on using the 7D to see if you can find any more advice if you chose that route. Keep in mind, with digital, you also have to be very wary of clipping your exposure of the screen.