FAQ
Q: How should I rig the screens?
Q: How can I learn more about compositing?
Q: Is there anything I can do to prolong the life of my screen?
Q: How can I clean the screen?
Q: What if a rental screen gets dirty?
Q: What is traveling matte?
Q: What is “chromakey”?
Q: What is Digital Green®?
Q: What is chroma green ?
Q: Is green screen rental possible with your company?
Q: Do your materials work for “virtual sets”?
Q: Do you supply “digital backgrounds”?
Q: Can your screens be used under water?

Q: How should I rig the screens?
A: Here’s a brief description of rigging a small screen using a SpeedRail® frame. There are additional images available in the Products Section showing overlapped screens and several styles of frames as well as a close-up of our ties. Small screens can be provided with a pipe pocket on one side so that a pipe inserted in the pocket can be suspended between two C-Stands. Larger screens may require heavier-duty frames like the “rock-n-roll” truss.

Q: How can I learn more about compositing?
A: Check out the many excellent resources in our Links section. For in depth instruction on compositing consider taking Jeff Foster’s “Green Screen Production Master Class” at Udemy

Q: Is there anything I can do to prolong the life of my screen?
A: If you are using the screen in a “limbo” shot where your subjects are standing on it, you should protect the screen from the floor by using industrial carpet, craft paper or a clean tarp on the floor or making sure the floor or carpet is quite clean before you lay the screen down. You should then provide carpet around the perimeter of the screen and ensure that your subjects wipe their feet on it before they walk on the screen. Try to keep unnecessary liquids like soft drinks and cleaning agents away from the screen. Acidic substances can cause orange stains on Digital Green® screens that will not wash out. Most other dirt is washable – see the instructions below. The screen should also be protected from excessive unnecessary light, especially direct sunlight and HMI, as these will in time cause a desaturation of the brilliance of the color. Therefore save lights on the screen whenever possible. In a daylight shoot in direct sunlight, provide for a cover such as muslin to be placed over the screen when you’re not actually shooting.
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Q: How can I clean the screen?
A: The screens are washable, either at home or at a commercial laundry. The basic steps in cleaning the screen are:

  1. remove the ties
  2. treat any significant stains
  3. wash the screens in cold water using Woolite® and fabric softener
  4. dry the screen in a dryer on low heat
  5. reattach the ties

You can also use a non-bleach stain treatment on heavy stains. We’ve found a terrific stain remover called “Kids’N’Pets” from Paramount Chemical Specialties, Inc. that removes most stains almost magically without damaging the screen – you may be able to find it at Target or Walmart locally, but you can also order from their website or from Amazon. A similar product is LA’s Totally Awesome cleaner and degreaser which we find at our local 99 Cents Only store or online. We spray it directly onto any stained areas of the screen, and then let it sit for a couple of hours before laundering. (If you have another favorite product, before using it extensively, please test it on a corner of the screen to make sure it doesn’t remove the color along with the stain.)
The next step depends upon the size of the screen. If the screen is under 20 pounds (about 200 square feet) and you have a large home washer, or a laundromat with large clean machines, you can probably wash it yourself. If the screen is larger, find a commercial laundry with a large capacity washer, and a willingness to launder the screen in cold water with mild soap. In either case, wash the screen in cool water with Woolite®. Use fabric softener in the rinse water to avoid static electricity in the cleaned screen, and dry it in the dryer on low heat. (If you throw a couple of clean tennis balls in the dryer with the screen, the balls will keep the screen from tangling in the dryer, and it will dry more evenly and quickly.) If the screen is still damp when you’ve done your best to dry it in a dryer, just drape it over a clean surface (not in direct sunlight, of course) until it’s completely dry. When the screen is dry, reattach the ties at approximately 8 to 9 inch intervals around the edges of the screen, and you’re ready for the next shot.
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Q: What if a rental screen gets dirty?
A: If the stained screen is a rental, we’ll clean it when we get it back. Charges are related to the weight of the screen and simply cover the laundry expense unless the damage is permanent. If you know you re going to be using a rental screen in an unclean environment, let us know ahead of time – we have older screens that are still usable and will cost less to repair or replace if damaged.
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Q: What is traveling matte?
A: Traveling matte is a motion picture term of art referring to a matte that moves, or travels, from frame to frame as distinct from a hard matte that remains stationary.
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Q: What is “chromakey”?
A: Chromakey, historically a video term of art, refers to a matte derived from a specific primary color, i.e. green, to provide a traveling matte for composite imagery. The terms are not exactly synonymous since a traveling matte may be derived by a variety of techniques, e.g. rotoscoping.
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Q: What is Digital Green®?
A: Digital Green® is a registered trademark of Composite Components and refers to a color difference matte background, one of the Digital Series™ of matte backings, exhibiting the very specific color co-ordinates and luminance values required for superior composite imagery and as specified in the patents associated with it.
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Q: What is chroma green?
A: Chroma green is simply a generic term for a green matte backing or process. It doesn’t designate any particular chromatic values beyond basic green color which includes a huge variety of hues.
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Q: Is green screen rental possible with your company?
A: Yes, our superior quality green screens are available for rent or purchase.
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Q: Do your materials work for “virtual sets”?
A: Virtual set technology was central to the design of the Digital Series™ backings. Virtual set technique particularly requires the ability to hold, or “carry” shadows from the original photography into the composite image. The Digital Series™ backing luminace provides excellent “quiet” reproduction of shadows.
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Q: Do you supply “digital backgrounds”?
A: While we do supply the greenscreens, the term “digital backgrounds” refers to the actual scenic images composited via color difference matting, so, no, we don’t supply such images.
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Q: Can your screens be used under water?
A: Yes, our screens worked underwater in Water World, U-571, Sphere and others. Both screens and painted backings worked in The Guardian.
If you plan to shoot underwater, please give us a call to discuss the requirements for handling our screens. Even more importantly, be sure to hire an experienced underwater crew! See the references below.
Here are a couple of reactions from VFX Supervisors with good credentials in this area, along with contact details for their recommended underwater specialists:

VFX Supervisor Jeff Okun: Jeff says, “Pete Romano is my favorite underwater guy! As you and Jon are my favorite matte and screen specialists!”

HydroFlex, Inc. – Pete Romano
301 E. El Segundo Blvd.
El Segundo, CA 90245
Phone: (310) 301-8187
Fax: (310) 821-9886
Web: www.hydroflex.com
Email: H2Opros@hydroflex.com

(Jeff has also done extensive underwater work – CutThroat Island, Deep Blue Sea, Sphere and Red Planet – and is willing to take questions – call us for his contact info.)

VFX Supervisor Peter Donen: (The following exchange took place in 2003 between our prospective customer and the late Peter Donen who supervised the extensive underwater shoot off Malta for U-571 and who gave us permission to quote him.)

Q: We are filming a character swimming underwater in various phases of a transition that will require prosthetics, wardrobe changes, body suit, etc. I expect we’ll do a combination of coverage from 3/4 behind, profile tracking, swimming toward and away from camera with camera static & tracking with character. We may have the character swim through various pockets of light along the way.
A: You are being quite ambitious here. Some of the shots described are relatively easy, some really hard. Buoyance control for the actor with bodysuit and wearing all that rubber is a problem as is the temperature of the water. This is many days work as you have described it. Trust me on this one, been there, got a collection of t-shirts.

Q: What did you find was the best screen color for working under water?
A: Both blue and green have been successfully used underwater. My personal preference is green, although on Devil’s Advocate and Water World, Stephanie Powell used blue very successfully. The more important issues are water clarity. I cannot stress enough the necessity to get as much clarity as possible out of the water. The less clarity, the more contamination from the screen and from the various lights. Liquid and gaseous chlorine in the water is far preferable to powdered chlorine for clarity purposes. Imagine that you are shooting in a HEAVILY smoked room. Those are the issues. I have had to bring in additional filtration as well as chemicals to settle out particulates in the water. On U-571 we filtered down to 5 microns circulating all the water through the filter once every 12 hours, but this was a HUGE tank, approximately 50 yards in diameter and 40 feet deep. I wish we could have circulated more as by the end of the day, the water was getting cloudy, and we needed 70 feet of visibility, something on the order of the clarity at Sea World in the tanks. You need to limit the number of people in the water as much as possible, and those people should be VERY experienced. The reason for this, is that experienced scuba divers have good buoyancy control, keeping them off the bottom, which means that any settled particulate stays out of the water. Don’t forget that underwater you will be working very close up with wide angle lenses. The water effect is to lengthen the effective focal length by about a third (see the articles in American Cinematographer Manual for reference). Thus a 24 becomes effectively a 32. This means that you are often in the zone of contamination (illumination wise). Steph preferred blue as it allowed her to stay a bit further from her subject. Water sucks the colors out of light. First Infrared, then red, yellow, green, blue, ultraviolet). Thus the exposure on the blue screen remains longer than on the greeen. There are up sides and down sides for both. Green gives you greater separation, but more contamination, and you have to work closer to the screen. Sorry, no easy answer here. My suggestion is to test.

Q: What fixtures and diffusion techniques (if any) did you use to light the screen?
A: We used underwater fluorescents to illuminate. Available through both Pace and Pete Romano. Diffusion is not the problem, it is more the opposite, controlling spill. Again, water absorbs light quickly. 100% of the red light is gone in about 30 feet. Any duvatine placed in the water, such as from 4x4 floppies will be ruined, so budget accordingly and don’t cheap out, use new, it is cleaner. The chlorine will bleach it out. However, I have yet to see, damage to Digital Blue™ or Digital Green® screens, but the tempo type screens are toast in 12-24 hours of submersion. The chlorine again being the culprit.

Q: And most importantly, what pitfalls should we be aware of that might choke our air supply and turn US green?
A: My suggestion is to hire a GREAT divemaster and safety crew as well as using a film crew that has dive experience working not just sport experience. Working underwater is very different from sport diving. Most of the crew should be working without fins, it is easier, and kicks up less silt which exists even in the bottom of a clean pool.
This is no place to experiment. I suggest Jim Pearson at CineMarine / Cinema Rentals. Diving is serious business, and even diving in about 15 feet of water can be dangerous, especially in a work environment. It is possible to suffer decompression sickness in quite shallow water when working, as with bounce diving (up and down like a yo-yo) you can supersaturate the body tissues with nitrogen far more than you would get normally even just staying at that working depth. You will need an olympic sized diving pool probably as a minimum 15 feet deep, you need space above and below the actor, something not often though of, otherwise you will be too close to the surface and it will get into the shot. Surface issues are a problem, both from a lighting viewpoint and from seeing it, bubbles also are a problem. About half the light shone on the water is reflected off, so you will lose a stop just getting through the surface. GFI (ground fault interrupts) on ALL lights and power are needed, and it is easier to get big units on the surface to get an overall level than to put them underwater. I floated a silk on the top of the tank on U-571 to make it look like we were working deep (no surface ripples on photographed objects), but this adds risks as the divers cannot then go straight up should there be a problem. Working days for the underwater crew is short, hypothermia, even with wetsuits, and exhaustion being issues. Stay clean, stay safe, this is a dangerous work environment which looks deceptively benign. Hope that this has been helpful.

Peter Donen (Partial Credits: U.S. Marshals, U-571, Bourne Identity, The Italian Job. Peter supervised the underwater shots pictured on our site for a commercial.)

CineMarine Team – Cinema Rentals, Inc.
25876 The Old Road, Ste. 174
Stevenson Ranch , CA 91381
Phone: (661) 222-7342
Phone 2: (877) 877-9605
Fax: (661) 253-3643
Web: www.cinemarineteam.com
Email: cinemarentals@aol.com
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