Improve The Quality of Your Green Screen Footage by Filming Tight

By David Carthage | Published: April 9, 2011
Here’s a trick you can use on shorter chroma key green film projects for creating a crisp and clear video that you want to export at a higher pixel resolution for your final video file than your camera is capable of capturing.  Sound impossible?  It’s not, and I’ll explain how to do it, but what you’re going to more widely use this technique for is improving the clarity/definition/ resolution of your green screen footage across the board by filming your actors as tightly as possible and then scaling down the size of the actor footage when positioning it into your edited chroma key composite.  That’s the tip right there!  In this way, you make intelligent and full use of your camera’s precious sensor pixel real estate and end up with footage of your subjects, that you’ll comp into your final keyed scene, that is higher in quality than if you were to do the typical thing most newbies to the chroma key technique do.  Most make the mistake of filming their subjects at a distance and zoomed out such that they appear in the camera frame the size the photographer wants them to appear in the final edited scene, in his final film project.  The problem with filming this way is that you’re only taking advantage of a fraction of the camera’s image space to capture with, and so you end up with lower quality footage of your subjects at the end of the day.  If instead you film your subjects together tightly and so that they all barely fit within the frame, together–as tightly as possible–you end up with a more high quality green screen footage to work with later on when you piece together your final composited video project.

green screen footage demo Improve The Quality of Your Green Screen Footage by Filming Tight

Shooting green screen footage like this is the standard practice among professionals because it both results in better image quality and because the increased resolution you will film your actors in sharpens the edge that separates them from the green screen behind them, to the camera, and this results in cleaner, better looking keys that have less noise around the edge of your actors to fix up in post production.

And as I said, you can actually create final movies that are larger in frame size than what you video camera is capable of recording, and still maintain full quality (with no stretching or magnifying the the image to make it larger, and no degrade in the picture quality).  This is a great tip that can help those on a budget, who aren’t using super high def cameras to film with, but who still want a high resolution end video.  By high resolution, I mean 1080p, for example.  This is an important technique to use if you need to create high definition video with a lower definition camera, because if you try to accomplish this by simply upscaling your footage the standard way of magnifying the image (without fancy, expensive interpolation software) and then view it on a screen capable of displaying high def video, you’re going to find it looks awful: grainy, blurry, and just plain bad.  But, using his technique of filming chroma key subjects as tightly as possible will help get your around this problem.

You can even take this chroma key technique one step further if you have the time.  If you have a shorter video project and a bit of time on your hands, and you really want to to take this filming technique its fullest extent, you can film each individual on-camera element individually, just tight enough so that each piece just barely fits inside the shot, and then composite everything together at the end when editing in your computer with your video compositing software.  This takes much more time to do, but it results in a much higher picture quality if you execute it properly and take the time to position your elements carefully in your compositing software.

If you’re filming green screen footage, I encourage you to practice this technique.  Start small and practice with a 10 second clip: take an actor, film her with whatever parts of her that will appear in your final video as tightly as possible, so that she just barely fits within the camera frame throughout your shot, and then scale her down in your editing program to a smaller size, to fit within a larger scene, potentially (if you desire) of a higher resolution/definition (example: shoot your subject at 720p and then create a video project that is 1080p and do this.)  With practice, this will become second nature to you, it will become your default method of shooting green screen footage, and you’ll end up with higher quality video, at the end of the day.  Cheers. -David Carthage

Technorati Tags: , , , , , , ,

Posted in green screen footage | Tagged , , , , , , , | Leave a comment

Green Screen Lighting: Dealing With Color Bleed and Green Spill

By David Carthage | Published: March 30, 2011

Color bleed is a common problem filmmakers run into when utilizing chromakey green screens in their video and photo projects.  Color bleed, or “green spill” as it’s commonly called when working with chroma green, is the reflection of the chroma key background’s color onto the filmed subjects.  You’ll often see it around the edges of your actors when you look at your green screen footage, and it can be a pain in the ass because it will often screw up your key later on in post production: the edges of your talent will key out improperly and make your shots look unprofessional, cheap, and not believable.  As always, establishing proper green screen lighting is the biggest challenge you face when working with this compositing technique; the quality of your results largely rest on how well you light your green screen and your subjects, and if you’re going to achieve quality results, you’re almost certain to have to take a few measures to handle the problem of green spill / color bleed that most filmmakers face when working with this tool.

green screen lighting color bleed green spill Green Screen Lighting: Dealing With Color Bleed and Green Spill

 

So how do you get rid of green spill, or avoid it in the first place?  It turns out there a lot of techniques you can use and things to take into account to deal with color bleed, and I’m going to go over the most popular ones here:

1) Keep your subjects as far away from the green screen as you can.  The further away from the green screen your actors are, the less color bleed will show up around the edge of your actors.  If your talent is acting close to the chromakey green, they are very likely to pick up a ton of green spill, and it will make your job of keying the green screen footage later on a bit of a bitch, to be blunt.  So keep your actors at least five or six feet away form the green screen at all time when filming.

2) Light your chromakey green screen independently from your talent.  You should be using two or more lights to illuminate the green screen, and then a few different lights (set up in the 3 point lighting setup, or however you do it) to light your subjects.  If you try to use the same lights to illuminate your subjects and for your green screen lighting, your subjects will cast shadows onto the screen, which will screw up the key and create a type of “shadow bleed” around your subjects that screws up the effect and makes it look unprofessional.  Also, part of the 3 point lighting setup is using a hair light (or a “back light”).  Using this light to illuminate the outline and the shoulders and hair of your subject will go a long way in cancelling out the green spill that’s coming off the screen and pouring onto your actors.  So light your subjects independently from your screen, and make sure you use a back light/hair light in in the process.

3) Use a colored light gel on the back light for your actors.  Light gels are used on lights in the special effects industry specifically for the specific purpose of cancelling out color bleed, and you can buy them in film supply stores.  If your screen is chroma green, go with a magenta colored gel; and if using chroma blue, go with an amber gel (sometimes referred to as “bastard amber”).  You place these colored gels on your subject back light/hair light lamp, and the gel project the complimentary (opposite) color of your chromakey screen onto the outline of your actors, to cancel out the color bleed reflecting off your screen.  When you utilize these light gels properly, you’ll end up with less or no color bleed.

4) Use the same gels on the lights illuminating your green screen.  Some filmmakers do it this way and find it works better for them.

5) Establish the all-important even green screen lighting, but have the screen lit darker than your subject (lit less intensely than your subject).  In other words, light your actors more intensely–with more light–than your green screen.  You still need to have the green screen lit evenly, but have it be just a little bit less intensely lit (about 1 f-stop) than your actors.  This will work very well in preventing green spill if you can manage it.  For this, you need to pay attention to the wattage output of your lights beforehand to set this up, but if you do this, you can really take out the spill problem altogether: with your actors lit up more than your green screen, the spill just won’t show up very much at all.

6) Use a matte spray on your subject.  You can buy special matte sprays to apply to your subjects so they absorb light (including color bleed) instead of reflecting it.  These are effective and worth looking into when working with naturally reflective subjects, such as actors with shaved heads, metallic and chrome objects, etc…  These things naturally reflect light, and so green spill tends to be especially nasty with these objects, and so using a matte spray can go a long way in helping you film these things in front of chromakey green.

7) Software can sometimes handle it after the fact, depending on how bad the color bleed is and how good your chroma key software is.  If you have a good chroma key software program for editing your green screen footage, you can apply a special filter that specifically handles the color spill problem for you, as in Adobe After Effects for example.  Now, this isn’t a magic solution that will work in extreme cases; the quality of your results are always going to be directly related to the quality of the footage you capture with your camera in the first place, but it can really help out and is a simple way of handling green spill if you have just a little bit of it deal with.  I wouldn’t rely on this strategy alone for dealing with green spill, but it is something to use if you have just a little bit of color bleed left over, after doing everything else to eliminate it.

8 ) Use a chromakey blue screen instead of a chomakey green screen.  It turns out that blue really beats green in this particular arena, because blue reflects far less noticeably onto subjects.  Green spill is typically much more dramatic than blue spill, with a given setup and all other things being equal.  So if you’re trying everything you know of and you’re still not getting satisfactory results, you may want to switch to using a blue screen for your shot, instead.

By following some of the above and combining a few of them, you’ll be able to eliminate the color bleed problem.  It does takes work though–anything involving a chromakey green screen does.  The skill of compositing with chroma key is not something anyone is born with; it’s an art form that is acquired through repeated practice, diligence, and paying attention to what works and what doesn’t, and keeping notes.  Getting your green screen lighting set up properly so your green screen footage keys out effortlessly takes work: you have to test out different setups and positions with the lights and different distances between actors and lights and the screen and experiment.  There is no one-size-fits-all solution to any of this.  But with that said, utilizing a few of the above steps will help you a lot in reducing or entirely cutting out the green spill/color bleed problem.  So try them out, play around with it, and I hope that helps you.  And let me know if it does in the comments section below: I like knowing if this stuff is actually helping you out.  -David Carthage

 

Technorati Tags: , , , , , , , , , , , , , , , , ,

Posted in green screen lighting | Tagged , , , , , , , , , , , , , , , , , | Leave a comment

My Personal Chromakey Green and Rotoscoping Visual Effects Services, Now Available For Hire

By David Carthage | Published: March 17, 2011

Today, I’m opening my personal chroma keying and rotoscoping services to the general public for photographs, so you can send me photos you want to have keyed or rotoscoped professionally and I will do that work for you and replace the background with an image of your choosing.

So if you have a photograph that was shot against a chromakey green screen or a blue screen (or a whatever screen) and you want to have it keyed, but you don’t feel like investing the time and energy it takes to key it yourself properly and get it to look just right, and you would like someone else to do that grunt work for you, you can email the photograph to me and I will key it for you and do any visual effects you want for it for a total cost of $59 per photo.

chromakey green my personal service before and after example3 My Personal Chromakey Green and Rotoscoping Visual Effects Services, Now Available For Hire

I’ve been working with chromakey green screens for a long time and have been keying photos from professional shoots with models, brides, and families for a number of years now, and I’ve mastered the craft along the way.  Even if the photo has bad lighting, and there’s some other weird problems with it, chances are I can handle it, and in any case, you don’t pay me unless you’re happy with the end result.

Here’s how it works:  you contact me by email and send me the picture you want me to chroma key or rotoscope.  I respond with a price (if you have more than one photo, we work out a deal), and once we’ve agreed on that, I go to work and key the photo for you.  When it’s done, I send you a small version of the final photo so you can see the work.  If you’re happy with it, you pay me via PayPal and then I send you the final photo in its original size; and if not, you can let me know what changes you want, and I’ll make them, and if you’re still not happy with it, you don’t pay a cent and you can say “to hell with this, I don’t think I want to do this,” and there’s no harm done.

The cost for my time is $59 for one photo.  If you have pile of photos you want me to key for you, then we’ll work out a deal so you save a bit of money.  It’s a personal policy of mine to build long-term relationships with clients, so I believe in punctual service and fair pricing. Obviously I want to give you a fair deal and if you have a pile of photos you’d like me to chroma key, we’ll work out a deal so you get a reduced rate. And as for speed of service, if you have five or fewer images you send me for chroma keying, I strive to have them back to you within 24 hours. Every once in a while, especially when I’m traveling, it will take me 48 hours to get back to you, but again, I really strive to have them ready for you within 24 hours of you sending them to me.

If you’re interested in doing this, send me an email at chromakeygreencontact@gmail.com and use the subject line “personal chromakey service” for the message, so I know it’s from you and not some junkmail robot, and we’ll go from there.  Alright, speak soon!  -David C

 

Technorati Tags: , , , , , ,

Posted in chromakey green | Tagged , , , , , , | Leave a comment

Chroma Green or Chroma Blue? In Fact, Any Color Can Do

By David Carthage | Published: March 1, 2011

Chroma green is a specific color used by filmmakers and photographers in the arts to do digital background replacement keying. The green color is used because modern digital camera sensors are most sensitive to this particular color, but there are cases where other colors are more desirable. Blue screens, for instance, tend to work better with low lighting shoots because the color is a bit darker and doesn’t create as much color spill around the edges of actors and subjects filmed in front of the chromakey background. But the screen doesn’t have to be green or blue at all, you can use any color, usually–it will depend on which chroma key software you’re using, but all of the modern programs I’ve used allow you to select any color you desire, to key out.

chroma green whilte cyclorama studio screen example of different color being used Chroma Green or Chroma Blue? In Fact, Any Color Can Do

 

The chromakey green color works great for outdoor scenes shot during the day. The color blends in with the greens in the environment to produce a very natural looking shot. And just overall, chroma green is by far the most used color in a variety of different circumstances: on stages and in studios, for indoor and outdoor shots, it is usually the preferred color by professionals and amateurs alike.

But as I mentioned, it is entirely possible to use any color you want for chroma keying. You can use black, white, brown, purple, grey, even hot pink if you prefer–in fact, a “magic pink” is used in special circumstances sometimes by professionals in their shots! The vast majority of chroma key software allows for you to select the particular color range you wish to key out from your footage/photos, and so you can use any color you want for your chroma key.

The important thing to keep in mind, of course, is that whatever color you use for your chromakey background, all of that color will be replaced when you apply the key effect in post production. So if you use a white screen, the whites of your actors’ eyes will be keyed out, along with every other white thing that appears in your chroma key footage, unless you use a more advanced technique and put in the time and energy to specify which specific parts of the frame you want to apply the effect to.

The main reason chroma blue and chroma green are used far more frequently for this is because they are relatively “extreme” colors, in a sense, that are easier to avoid having show up in your shots.  They are both far away from any skin tone and normal hair color, and they are relatively unnatural colors in the man-made world of clothing, set props, and most other things you’ll typically stick in front of the camera on a chromakey shoot. In other words, these colors are easier to stay away from in your shots if you want to, so you don’t accidentally shoot footage that will be keyed out incorrectly or very difficult and more time consuming to achieve the desired key.

So as far as chroma key colors go, that’s it; it’s pretty simple stuff. I recommend trying out a few different colors for yourself if you’re working with a smaller green screen and you can afford to experiment a bit. In certain circumstances, some filmmakers SWEAR by using a taupe screen (that is, a taupe-colored chromakey background), claiming it keys out easier with less color spill on filmed subjects. Others refuse to use anything other than a chromakey black screen, and many professionals use chromakey white screens in specific contexts for photo shoots. Try them out yourself when you think it would be appropriate and see for yourself. As always, the answer for “what’s the best x?” is: “try a bunch of Xs out for yourself and SEE which one works best in your particular case.” Overall, though, if I could only have one chromakey background and I wanted it to be useful in a wide range of filming and photography scenarios, I would have a chroma green screen in my hypothetical filmmaking bag of tricks, simply because of its overall versatility and ability to consistently produce good looking, professional quality keys when it’s used properly. I hope that helps, and leave me some feedback in the comments area if it did; I’d like to know if these articles are actually helping you out.

 

Technorati Tags: , , , , , , , ,

Posted in chroma green | Tagged , , , , , , , , | Leave a comment

The Most Common Green Screen Lighting Problem Amateur Filmmakers Run Into, And What To Do About It

By David Carthage | Published: January 28, 2011

I’ve mentioned this before many times, but it bears emphasis in an article of its own because I keep seeing a lot of amateur filmmakers and photographers making this mistake again and again with their green screen lighting, and it’s basically the barrier that separates people doing a poor, amateurish job with their chroma keying from them achieving a professional looking result, instead.

green screen lighting models with bad chroma key The Most Common Green Screen Lighting Problem Amateur Filmmakers Run Into, And What To Do About It

 

What most of these people are struggling over is fairly simple stuff; chromakey green screen work is not complex: it is actually a fairly simple art, but it can be difficult and frustrating if you don’t know what know exactly what to do with your lighting so that your chroma key software produces nice, clean keys (background replacements), so I want to cover one of the most essential things you need to get right for your this effect to work properly, as it’s meant to.  If you get this right, your key will look great and you won’t have many problems leftover to deal with, but if you don’t this, your keying can turn into a small nightmare.

So what is this problem I see everywhere?  It has to do with people doing a poor job with their green screen lighting: they’re not lighting their chroma green screen evenly.

green screen lighting models with uneven green screen lighting The Most Common Green Screen Lighting Problem Amateur Filmmakers Run Into, And What To Do About It

 

When it comes to green screen lighting, the prime directive is simply this: light the green screen evenly.  Most people have trouble with their chroma key effect because they do not light their green screen evenly.  In order for the effect to work properly, the screen needs to be lit evenly all the way across it, so that it presents itself as one single color tone to the camera.  If you can make this happen, you remove about 90% of the problems people run into when working with this art form.

green screen lighting even lighting The Most Common Green Screen Lighting Problem Amateur Filmmakers Run Into, And What To Do About It

 

So exactly how do you make your green screen appear as one solid even color?  Two things: First, you light the chroma green screen evenly with your lights; and second, you don’t introduce anything onto the screen that messes this even lighting up!

Lighting your chromakey green screen evenly with your lights comes down to using a matte material (not a shiny one) for your chromakey green screen and then having enough of the same kind of light and positioning it in such a way where it illuminates the screen evenly.  You can use scrims and diffusers on the barn doors of your lights to help out with this, or you can just position your lights through trial and error in such a way where they overlap just right to give you even green screen lighting.

green screen lighting muslin with wrinkles The Most Common Green Screen Lighting Problem Amateur Filmmakers Run Into, And What To Do About It

 

And as for the second point–not introducing anything that screws up the even green screen lighting–I’m talking about shadows projected onto the chroma green, extra light coming from the lights you’re using to illuminate your actors, and wrinkles in the screen material itself, if you’re using a fabric chromakey green screen.  Any shadows that appear on the green screen are going to present themselves to the camera as a different color from the rest of the green screen, and so will not be included in the key effect later on (without extra work) when using your chroma key software program.  So to avoid casting shadows on the green screen, keep your actors at least five steps away from the screen when filming, and keep the actors out of the way of the lights illuminating your chromakey green screen.

green screen lighting light spilling onto chroma green screen The Most Common Green Screen Lighting Problem Amateur Filmmakers Run Into, And What To Do About It

 

As for preventing extra light from your actor/subject lighting setup from spilling into and screwing up your even green screen lighting, you do these three things:  

  1. Make sure you’re lighting you green screen and your actors independently.  Using separate lamps to light up each of these goes a long way toward preventing this problem from existing in the first place.
  2. Make sure your subjects are acting at least five steps away from the chroma green, and that they are physically positioned in a more advanced position toward the camera than the lights illuminating the green screen.  In other words, have your actors positioned closer to the camera than the lights that are shining light on the chroma key green screen.  This tends to keep the light you’re using on your actors even further away from the green screen, which results in it having a far less significant impact on your green screen lighting than the lights directly illuminating the screen.
  3. Always test out your lighting on-set first, with your actors and props and all the lighting involved, and reposition any lights as needed, so that when you look through the viewfinder of the camera, the chromakey green screen is appearing as a single even color, before you shoot and record any green screen footage.  If you follow these three steps, you’ll run into far fewer problems involving lighting your chroma green.

green screen lighting muslin with many wrinkles The Most Common Green Screen Lighting Problem Amateur Filmmakers Run Into, And What To Do About It

 

As for eliminating wrinkles your green screen, this will only apply if you’re using a cloth-like material for your green screen backgrounds.  If you’re using muslin cloth for example, you want to hang it on a wall in such a way that there are no wrinkles in it.  If this means you have to iron the screen first before using it, do it.  If this means you have to buy more pins or thumb tacks or clamps or tape or whatever to accomplish a wrinkle-free setup, do it: a little work now, before you start shooting, goes a long way later on when editing in keeping your job quick and easy, instead of long and arduous.

So again, the prime directive with green screen lighting is to light the green screen evenly.  Do this so that the green screen appears to be one single solid color all the way across it, at all times when filming.  If you can do this one thing, you will sidestep so many editing problems later on in the process in post production and not even have to deal with them in the first place, because you removed the source of those problems before you began.  Lighting the green screen evenly will likely take a little more of your time, and possibly a little more of your money, but it is well worth that investment if you are serious about achieving professional looking chroma keys in your photo and video projects.  …And if you want the process to be easy and straightforward and to save your sanity, basically, instead of having to fight with the chroma key software for additional hours on end and wasting your time–that too!

 

Technorati Tags: , , , , , , , , , ,

Posted in green screen lighting | Tagged , , , , , , , , , , | Leave a comment

Chromakey Green Actors Need To Have A Vivid Imagination

By David Carthage | Published: December 28, 2010

With the passing of the Christmas holiday and with many of you sure-to-be-happy filmmakers all over the world with your new digital cameras and camcorders, many of you will be looking to make use of chromakey green in your film shoots to create great looking visual effects on the cheap. Using chroma key green backdrops allow you to create the sets of your dreams without spending a whole lot of time and money producing it in the real world, freeing you up to make your movie faster and a lot cheaper.

As I’ve mentioned many times before, your biggest concerns when filming with chromakey green are your lighting, your camera angles to ensure the screen will cover the whole shot and that they’ll match the “key footage” you’ll be adding in later on, and something that isn’t often talked about but that is crucial: you need to make sure your actors are capable of acting in front of the chromakey screen in a convincing way and have the imagination to do so.

Chromakey Green Test Your Actors Chromakey Green Actors Need To Have A Vivid Imagination
 
I was reminded of this by a recent interview Access Hollywood did with actor Emily Blunt, where she spoke about the frustrations and challenges of working on a movie project that required a lot of green and chromakey blue screen work: many actors find it easy to act with costars on stage, but when put onto a green screen set with little more than a few props and a few markers for later on in the keying process, some actors find it tough to act convincingly. They get distracted and their imagination fails them. So you need to find actors who are good with their imagination, who can make-believe and make you believe with their performance.

If you keep up on celebrity news, and even if you only browse through the gossip rags in the grocery store line, you’ll see actors being asked questions about what it’s like to act on a green screen set every once in a while. And invariably, you get two answers: either “I loved it; it was great” or something along the lines of “it was HARD!!–there was a tennis ball I had to act out my scenes with and pretend was the other person and….” In other words, some actors have a very tough time performing in front of the chromakey green because it’s an exercise in imagination …they don’t have. These actors have to act in front of the camera, in front of the production crew and the other actors, if any, as well as conjure up the images of the final scene in their head without them actually being there, on-set, for this actor to play off of and get direct inspiration from. The actor’s imagination has to become part of that source of inspiration, instead, and this is a skill that some actors have more than others.

So it’s important to screen test actors for their green screen acting when doing your casting calls and testing actors for the roles in your movie. If you’re going to be shooting a film, movie, or video of any kind that involves a lot of green screen work, you’re going to produce a better picture if you test you actors out hardcore in front of a green screen setup right at the beginning to see if they can really pull it off. You may have seen them act on real sets before, but acting in front of a chromakey green set is an entirely different experience in a lot of ways and until you see them do it, you don’t know if the actor is going to be able to pull it off.

So test them out and see for yourself. With your new camera and film loot from Christmas, and whatever other bs holidays you like to celebrate, you’ll probably already have the tools to be making your films with green screen effects! Just get out there and do it!

Chromakey Green Example Of Actors Without Good Imagination Chromakey Green Actors Need To Have A Vivid Imagination
 
A final thought to wrap this up: have you ever found yourself watching a scene in a movie and suddenly realized that it had been filmed using a chromakey green screen, just by how “off” the actors are in their acting? Perhaps you’re watching an action flick with explosions and massive drama happening around the actors on screen, but the actors look strangely calm for some reason? A good example of this can be seen all throughout the recently released film The Chronicles of Narnia: The Voyage of the Dawn Treader. In many scenes, the stars are in this stunning-looking world, yet the expressions on their faces look would have you believe these kids were having a boring conversation in the school courtyard over lunch… it just doesn’t match. The entire film is a great reminder for this point: that you need to test your actors for their ability to act convincingly on camera when nothing is really there for them to act with on a chromakey green set, and to monitor this when filming your picture to ensure you have the emotional performance there, on screen. If you get this right, your picture can look amazing. If you don’t, your film, that should have looked great, will otherwise be full of performances that are lame and not at all convincing to any audience member who isn’t already half asleep!

 

Technorati Tags: , , , , , ,

Posted in chromakey green | Tagged , , , , , , | Leave a comment

Three Important Green Screen Lighting Factors To Keep In Mind

By David Carthage | Published: December 19, 2010

I look around and I see a lot of amateur filmmakers asking questions like “how do I light my green screen? What about the actors? What lights/lamps do I use for my green screen lighting?”, and “where should I position the lights on the set to get the chromakey green screen to key out properly?”

All very good questions, and I’m going to answer them here, now.

Green Screen Lighting Studio Lighting Three Important Green Screen Lighting Factors To Keep In Mind

 

So the first, how to light your green screen: You want to light your green screen and your actors independently, with different light sources. Typically you’ll light your green screen with two or more lights, one on each side if you’re utilizing a bare bones lighting setup, but you’ll usually want to use more lamps to get the chromakey green muslin or posterboard or green painted wall (whatever you’re using for your screen) lit as evenly as possible across its entire surface.

When it comes to lighting your actors, the standard lighting practice is to use a three point lighting setup, involving a key light–the main light, which will be the strongest in your trio of lamps; a fill light, which is a less powerful light used on the other side of the actor to take away the shadow created by the key light; and then finally the hair light/back light, used to light the head/hair/shoulders/outside edge of the back of your talent, to prevent green spill/color bleed–light that bounces off your green screen and onto your actors, appearing as a green outline around their edges.

Green Screen Lighting Arri Lamps Three Important Green Screen Lighting Factors To Keep In Mind

 

What lamps to use: there are an infinite number of options to choose from, and you get what you pay for. If you can, opt for some nice powerful softbox lamps to light your screen and some other ones for lighting your subjects. You can buy sets of these for a couple hundred bucks from companies like Lowel, Fancier, PhotoSEL, or Britek. I’ve found that a good place for buying kits like this online is the green screen specialty store TubeTape.net, or you if you’re lucky, you’ll be able to find some steals on eBay. If you’re got money to blow, you can find premium light kits like the ones by Arri that cost into the thousands of dollars, if you’re a successful filmmaker or frequent lottery winner. But the majority of us amateur filmmakers are, to be blunt, poor, so it pays to know what is essential in your lighting so you can get the most out of the least and a couple hundred bucks for lighting is over your budget, you can almost always find cheap, halogen clip on work lamps from a local hardware joint and test and experiment with them until you have something that works for you, but this will tend to be more work because they won’t be color temperature balanced (I’ll explain later). The three factors you need to keep in mind when selecting lamps to use for a chroma green screen shoot are light intensity, light diffusion, and light color temperature.

The lights need to be intense and powerful enough to light your green screen evenly, but not so intense that they create hot spots. Digital video cameras are very sensitive to light and if you have too wide of a lighting intensity difference across the screen, or between the green screen lighting and the light hitting your actors, you’re going to run into overexposure problems and the shot won’t be any good for keying in post production. So you need lights that are strong enough to illuminate your green screen evenly without blowing out the image to white when viewed through the viewfinder of your camera. Also, when it comes to lighting your actors, the same principle applies: you don’t want their skin appearing as a giant white reflection, which will happen if the lighting is too powerful on them.

On the other hand, the more common concern with budget filmmaking tends to be that the lighting is too weak, so that it doesn’t do a sufficient job of lighting the chromakey screen evenly, especially if you’re working on a larger set. This can only be remedied by A) adding more weak lights to the equation to increase the overall lighting on the green screen backgrounds, or B) replace these lights with more powerful ones. Again, this applies to lighting both your green screen and your actors. You want to make sure you have enough lighting for filming your green screen footage because digital video cameras tend to get fairly grainy when shooting low light footage and it doesn’t look good.

And the other factor to be mindful of, diffusion, is related to intensity. Diffusion has to do with how the light spreads out, and you’ll typically want to use lights that are more diffused for lighting your chroma green screen and actors than the typical focused flashlight beam that some lights, like a bare light bulb, provide. If the beam illuminating your green screen is too focused and not diffused enough, it will not light your green evenly; you’ll have hot spots appear that overexpose your shot. And the same applies when lighting your subjects, although you need light them in such a way that they’ll be lit as if they were actually in the end result fantasy scene you’ll be creating in the computer with the chromakey effect, later on, so any guidelines given on how to light actors can only be just that at best: rough guidelines. So to take the harshness of a light down a few levels and soften in, you can use something to diffuse it. You can clip diffusion paper, like Cinefoil, along with special colored diffusion gels designed specifically for this, or improvise with some white umbrellas, clear egg cartons, or paper. You clip them onto the barn doors of the lights to unfocus and soften the beam of light coming from your lamps and spread it out more evenly, for more even green screen lighting or actor illumination.

And the third factor to keep in mind with your lighting is its color temperature. Measured in degrees Kelvin, color temperature has to do with how warm or cool your lighting is, or as some look it, how yellow or white the lighting appears. The thing to keep in mind is this: make sure your lights illuminating your green screen all match in color temperature. The goal when lighting a green screen backgrounds to have it appear as one single, even color, and if you have lamps of different color temperatures lighting your screen, the color of the screen is going to look uneven. So be sure to select bulbs of the same color temperature for all of your lights that will be lighting your green screen. What temperature of bulb used in lighting your greens screen is not really that important, just as long as when you’ve lit the screen with those lights and you’re looking through the viewfinder of your camera, the green screen appears as an even, chromakey green color, you’re good to go.

As for lighting your subject with different color temperatures, well that’s another article for another day. I’d recommend searching Google on this if you’re interested because there’s a lot of good information out there on color temperature already that will open your mind with just a brief bit of reading. Always remember that the goal in lighting your actors on a green screen set is to have them lit as they would be were they in the synthetic world you’ll be keying in later on in the editing process.

Green Screen Lighting Camera Check Three Important Green Screen Lighting Factors To Keep In Mind

 

So keep your green screen lighting in mind when filming: make sure your lamps are bright enough but not too intense, make sure you have enough diffusion that hotpots aren’t appearing, and make sure the color temperature of your lights illuminating the green screen all match. As for where to position your lamps, the answer is this: experiment with it. Again, digital cameras these days are very sensitive to light and you need to experiment with your particular setup to achieve a lighting setup that will work to give you even lighting across the green screen and light you subjects in the way you desire. You can also find some general guidelines on specific positioning of your lights in some of the past articles on this site, too. Cheers, my fellow chromakey green filmmakers!

 

Technorati Tags: , , , , , , , ,

Posted in green screen lighting | Tagged , , , , , , , , | Leave a comment

How To Chroma Key: An Overview

By David Carthage | Published: December 11, 2010

I look around the web and I see a lot of general questions about chromakey green and the process of using green screen backgrounds when filming and doing photo shoots. A lot of people know of green screens and blue screens, but few of them really know how to chroma key when actually filming or doing photography with the effect in their own media projects.

How To Chroma Key chromakey green tunnel How To Chroma Key: An Overview

 
What follows is a general overview of the process of using chromakey green. I post about once per week and in future posts I’ll cover each step of this process in greater depth, but this overview will get you started if you’re just getting your feet wet and wondering how to chroma key and use a green screen, yourself:

Step 1: Set up a green screen. You can buy your own or, in most cases, you build our own green screen using chromakey green materials you put together yourself. Most choose to build their own because it’s cheaper and because it lets you build the green screen that you need in your particular case, for your specific filming project. You can find our more about your options for green screen materials in a recent post I made.

How To Chroma Key studio setup How To Chroma Key: An Overview

 
Step 2: Light your green screen and your subjects. This is arguably the most crucial step because if you get this wrong, it will make your life hell later on when keying out the green screen backgrounds from your green screen footage, and if you get it right, you make the task easy and straightforward. You can read about green screen lighting in a recent article I wrote on this site, but in addition I’ll say that it’s important the lighting on your subject you film in front of the green screen match up as closely as possible with the lighting that exists in the alternate footage you’re going to composite in later on, so they look like they “fit” together and appear as one shot. If you don’t get this right, your keyed footage will look fake and this is probably the most common telltale sign that footage has been keyed–you’ll notice that something just doesn’t quite look right about the shot, and it’s this thing–the mismatched lighting in the two composited shots. You can play around with the contrast, brightness, and levels in your video editing program and get the two to match up a bit more closely if there is a minor difference in their lighting, but you’ll typically only fix minor green screen lighting problems that way and the more you do it, the more you’ll tend to degrade the quality of your footage, so do your best to get your lighting to match from the start so you don’t have to play around with too many of the chromakey green settings in your video editing chroma key software later on.

Step 3: Film your footage with your subjects in front of the green screen backgrounds. Make it count because once you’ve shot your footage, you’re stuck with it and, unless you can re-shoot your footage, you’re going to have to work with what you have. So check your green screen lighting through the viewfinder before you start filming, making sure it’s evenly lit, make sure your actors are far enough away from the chroma green screen and that they’re properly backlit so they don’t have any green color spill/color bleed on them, and that the rest of your shot is prepared, before hitting record on your camera.

Step 4: Import the chromakey footage into your computer, and get ahold of a video editing program that is capable of working with chromakey green footage and applying the key effect to it. Popular chroma key software programs people use these days include Adobe After Effects, Final Cut Pro and also iMovie for those using an Apple computer, Sony Vegas, Visionlab, or–if you’re keying photographs–the Cinematte plugin for Adobe Photoshop. There are a lot of these programs you can purchase online, but these are a few of the more popular ones.

Step 5: Edit your movie in that chroma key software and apply the effect. As there are many good chromakey green video editing programs out there, I’m not going to give specific advice right now on how to do it, but the quick answer is this: search google for “how to chromakey with (name of the software you’re using)”, and you’ll find a pile of guides instructing you on how to key with the chroma key software you are using in particular.

Step 6: Render/export the edited video that you’ve applied the chromakey effect and all of the rest of your editing to. Once you’ve exported the video, that’s all there is to it: you have your final video.

How To Chroma Key chromakey green lighting How To Chroma Key: An Overview

 
So that’s the process of how to chroma key in a nutshell. I’ll say again in closing that the biggest source of problems people run into when using chromakey green is the lighting. Make sure you pay attention to how to set up your green screen lighting properly because if you do, you’ll dramatically reduce the amount of effort and time you spend getting the green screen replacement effect to look professional when editing your video or photo. Aside from that, now that you know how to chroma key, get out their, film with your chroma green screen, and have fun!

 

Technorati Tags: , , , , , ,

Posted in how to chroma key | Tagged , , , , , , | Leave a comment

Green Screen Lighting: Standard Setup

By David Carthage | Published: December 4, 2010

When setting up a chromakey green screen that will actually work and be easy to key out later on when editing your footage with chroma key software, getting the green screen lighting set up properly is often the biggest challenge.  The goal when lighting a green screen is to illuminate the screen evenly so that the screen itself appears a single solid green color, with zero variation in color tone and lighting (ie: no shadows).  When chromakeying, few people outside of professionals go the distance from the start, before they shoot anything, to actually accomplish this proper lighting, and this is a big reason why so many struggle to achieve good results when editing and applying the chromakey effect.  On the other hand, those who accomplish this even green screen lighting significantly reduce their work later on and make the keying process much easier.  By going the extra mile before they start, they save themselves hours of work later on in post production with the chromakeying, especially if they have filmed a lot of chromakey footage.  So in this article, I want discuss the most common green screen lighting arrangement for a modestly sized screen that will yield professional results.

 

green screen lighting basic setup with basic lights Green Screen Lighting: Standard Setup

 

The standard lighting for a modest chromakey green screen is to have two lights illuminating your screen and three lighting your talent.  With this green screen lighting, you have one lamp on each side of your green screen background, a couple feet away from the screen, angled in at roughly 45 degrees, lighting it as evenly as possible.  Don’t place the lights too close to the screen because you’ll create “hotspots” on the chromakey green screen, like in the picture above–which is a bad example of green screen lighting–which go against the even lighting ideal you’re aiming for.   Then, you have your talent standing and acting physically further away from the screen than those two lights, behind the “line” of the them, so the actors aren’t creating any shadows on the screen.  The sole purpose of these two lights is to light the chromakey green as evenly as possible.  You can, and–especially if you’re filming with larger green screen backgrounds–often will use more than just two lights to light the screen, but we’re just covering the most common basic green screen lighting setup for a smaller screen, here.

In addition to lighting the chromakey green screen, you need to light the subject as well because only lighting the screen and not the actor will result in a silhouette effect.  Cameras will only focus on one “level” of illumination exposure and in this scenario, you have so far created two: one being the actor with not much lighting on her and two being the green screen that you have lit up with your two lights.  With these two different levels of exposure in your shot, and with such a difference in illumination between them, your photography of the scene will not capture both the chromakey green screen and your subject in the foreground properly.  So you need to light both the green screen backgrounds being used as well as your talent, and you need your green screen lighting setup to do so independently; it’s important to light the screen and actors independently, not with the same light, because to light both with the same light sources will create shadows, making it very hard for you to key the footage later on when using the chroma key software.  Using the same lights for both will also create “green bleed” or “green spill”, a green outline of reflected light around your talent that can really make your final chromakey effect look cheap and unprofessional.  So you need to light your green screen backgrounds and your actors separately, with different lights.

 

green screen lighting 3 point lighting diagram Green Screen Lighting: Standard Setup

 

When it comes to lighting your talent (or subjects), the industry standard is the 3 point lighting system, consisting of a “hair light” (also commonly called a “back light”), a “key light”, and a “fill light”.  The hair light is positioned above and behind the subject, shooting down onto her head and back. This light addresses the green spill that often appears around subjects in front of chromakey green.  Next you’ve got your key light, which is positioned somewhat head-on at your subject, but at a bit of an angle.  And then you’ve got the fill light, on the other side of the actor from the key light, taking away any remaining shadows created by the other two.  I’m purposely not being very specific here about the angles of the lights because you have to experiment with your green screen lighting to both set it up correctly with the equipment you have and to create the effect you are specifically looking for: lighting is tricky because modern digital cameras are very sensitive to light intensity and something referred to as light “color temperature” and you really need to experiment with the positioning of your lights to find the sweet spot that looks good through the lens of your camera.  But also, unlike your chromakey green screen, your talent can be lit as dramatically as you want; the trick is in lighting your subjects without screwing up the even lighting of your background!  For each shoot, unless you’re working in a professional chromakey green studio, you really need to set up your green screen lighting and then have your actors stand in place on set while you adjust the lights and check the result through the viewfinder of your camera, whether you’re doing film or photography, because that’s the only way you’ll see if your lighting is “working” for you or if you need to make an adjustment.

 

green screen lighting cyclorama lighting Green Screen Lighting: Standard Setup

 

You can use more that three lights for your subjects, and the more professional studios will because of the increased flexibility it affords you when shooting and the requirements of shooting on larger green screen backgrounds, but for your basic, modest home-grown green screen setup, the 3 point lighting setup will yield professional looking results when lighting your talent, if you set it up correctly.

 

green screen lighting a more pro setup Green Screen Lighting: Standard Setup

 

That covers the standard green screen lighting setup for a chroma green screen.  Now, without going into a lot of detail here, you might be wondering what kind of lights you use to light green screen backgrounds.  On a budget, many use standard workshop lights from department and hardware stores.  They provide decent lighting for smaller green screen setups and, if your screen is bigger, you can buy a few more of them without breaking the bank.  They’re cheap and get the job done quite nicely for smaller green screens.  If you want to go pro, you’ll start using more powerful studio lights with diffusers, umbrellas, blinders, and other more expensive higher-end equipment.  Always remember that the object of the game is to light the chromakey green evenly; the bigger your screen, the harder this becomes, and that’s when you’ll start to use this more expensive equipment that is specifically designed for larger green screen backgrounds.  No matter what the size of your screen, by putting in the energy to get your green screen lighting setup effectively from the start, before you start shooting your footage with your cameras and actors, you’ll save yourself a ton of time and energy later on when editing and make the whole chromakey green process much easier for yourself.  Until next time, happy filming. -David Carthage

Technorati Tags: , , , , ,

Posted in green screen lighting | Tagged , , , , , | Leave a comment

Green Screen Backgrounds Materials Comparison

By David Carthage | Published: November 26, 2010

This article discusses and compares the many materials available to you when constructing or purchasing your own green screen backgrounds, with the primary intention of aiding those in the process of deciding to build their own.

So, you’ve decided to start working with chromakey green screens for filming or snapping photos.  The first question you’ll want to answer is “do I buy prefabricated green screen backgrounds or should I make my own?”  It’s less effort if you buy a pre-built green screen setup, but it will cost you more and it won’t be customized to fit your particular filming needs in all likelihood.  This is why the vast majority of amateur filmmakers construct their own chromakey green screen.

If you’ve decided to build your own, you really only need two things: the green material and a mounting platform for it, such as a wall to tack it to or a rail to hang it from, a stand, or human slaves.  I’m kidding.  …Sort of.

While you can build green screen backgrounds out of many different materials, I need to emphasize that the green screen materials used should be as least reflective as possible, and have a consistent color across its whole surface.  Do not make the mistake of purchasing a green cloth or material that has a pattern on it because that will screw up the chromakey effect later on when editing your green screen footage with your chroma key software.

As I said, you have a lot of different material options for your green screen, ranging from the high end stuff that costs hundreds if not thousands of dollars, all the way down to the low end goods that are cheap but that don’t give you that professional look you’re going for because they introduce little visual glitches into the final result that give the viewer the impression that something is just not quite right about the shot.  And then you have a bunch of mid-range options the majority of us filmmakers and photographers utilize.  To make it easier for you to select an appropriate material for your own screen, I’m going to compare the budget and mid-range options here:

Green poster board:  commonly used by those on an ultra budget, it’s cheap and can work well if you have the time (and no doubt: patience) to set it up properly.  You’ll find it in the school supplies section of your local department store, in a lime green color. It’s cheap, and if you’re looking to build a small to medium size screen, you can create one for around $20: just connect all the pieces together with some clear tape on the back sides (so you don’t introduce reflections), and you’re set.

Pros: it’s cheap, and can yield decent results if you set it up carefully.

Cons: it’s fragile and finicky, difficult to move around without wrecking it, it can’t be washed, and takes a long time to setup.

 

poster board chromakey background Green Screen Backgrounds Materials Comparison
photo courtesy of Rosalind Gash of www.Bloganista.com

 

Wider green paper sheets:  similar to the poster board option, only a larger version of it.  Paper can be stored easily and is smooth, but because of that, is a bit reflective: paper has a slight sheen to it and that makes your job achieving even green screen lighting and achieving a consistent color all the way across it a bit more challenging with this particular option.

Pros: it’s cheap.

Cons: similar to the poster board, it’s fragile, difficult to move around without wrecking it, takes longer to setup than other materials, and once it gets dirty, you pretty much have to turf it.

Plastic green sheets:  they’re marketed around the internet as a cheap option for creating your own chroma green screen, but that’s typically just what they are: cheap.  They’re usually small (bigger is almost always better in chroma key, for many reasons), they tend to rip easily, and worst of all: they reflect light a lot more than your other material options.  Plastic sheets can work for simple shots with minimal use of the screen, such as standard headshots, but they are otherwise to be avoided.  On average, they’ll cost you about fifteen American dollars for a fairly small sheet.

Pros: they’re easy to transport and don’t wrinkle easily.

Cons: they’re typically small, reflective, can rip easily, and are overpriced for what you get.

Green bed sheets:  you can go to the bedroom section of your local department, hardware, hobby, or fabric store and buy a green bed sheet or something similar to hang up on your wall for your green screen backgrounds.  They’re cheap and they’re light, so they’re easy to move around, but their downside is that they tend to wrinkle easily if you don’t take care to fold them or roll them up properly when storing or for transporting, and they also tend to be quite thin, which frequently allows you to see what is behind them when hung up, so you need to hang them against an evenly colored wall when shooting with them in order to achieve decent results when applying the chromakey effect later on in editing.  Hang the bed sheets on the wall with green tacks and, when doing so, make them as tight as possible to avoid any wrinkles in the fabric so you can light the screen evenly.

Pros: they’re very cheap, very light. 

Cons: because they’re so light, they’re difficult to mount without wrinkles (which create shadows), and they have to be mounted on a wall, so they’re not exactly the most versatile material around.

Green felt cloth:  many photographers use felt cloth for their green screen backgrounds.  The felt cloth is portable, can store away easily, does not reflect light very much at all, but it can wrinkle if you’re not careful, which creates shadows, and shadows in your green screen background make the chromakey replacement process much more time consuming when you edit your green screen footage.  Felt cloth varies in price depending on the quality, but you can generally find it at most hobby and fabric stores for around $5 or $6 per square yard. Overall, felt cloth is a decent mid-range option.

Pros: absorbs light very well and can yield very professional looking results.

Cons: fragile and delicate, difficult to clean.

Chromakey green muslin:  muslin is a type of cotton fabric that is durable and washable and works particularly well for this kind of greenscreen compositing work, typically costing around $50 for a 9′ x 12′ sheet, or 90 bucks for a 9′ x 20′ sheet if you shop online at some of the more prominent film supplies stores.  BUT, if you go to a few local fabric stores in your area, you’ll often find they sell very similar quality muslin sheets for significantly less than that, so shop around first before buying.  They don’t rip easily, you can wash them, plus you can hang them up with tacks on a wall and they’re thick enough to mount well with a stand. Using muslin cotton for green screen backgrounds is a very popular mid-range option because of its great effectiveness and versatility relative to its price.  It is more expensive than buying a bed sheet, but your film footage and photographs will key properly with less effort.

Pros: can yield professional results, is durable, very versatile, easy to transport.

Cons: can be expensive if you don’t shop around.

 

chromakey green muslin Green Screen Backgrounds Materials Comparison

 

Painted green wall: If you need a big green screen for your shoot, then you may consider painting a wall or two in your house in chromakey green and creating a kind of green screen studio of your own.  If you buy the specifically marketed chroma green video paint you see around the internet for this, you’re likely to pay at least 50 dollars for a bucket of the stuff.  Is there anything special about this paint?  Not really.  Yes, you’ll get a perfect chroma key green color paint, and it will be a flat paint, helping to avoid reflection; but you can create almost the exact same paint that will work just as well at your local paint shop for only a little more time and effort and a lot less money.  Painting a wall and creating a permanent filming studio in your home can produce great results, but you need to have the space for this and the patience to do it right.  If you’re going to do this and you’re going to go to the local paint shop to mix your own green screen paint, make sure you by a flat “matte” dull paint that will not reflect light very well.

Pros: economical if you need a big green screen and you have a room you can transform into a studio, can achieve very good results with it, low maintenance once setup.

Cons: more difficult to clean than some of the other options, requires more time to set up, not portable.

 

chromakey green painted studio Green Screen Backgrounds Materials Comparison

 

There are other materials being used for chromakey green screens out there, and if you get creative I’m sure you can think of some more you could try out, but these are the most popular materials used. 

Your choice of material will depend on the requirements of your shot: how big of a screen you need, this size of your budget, and whether you need to take the green screen with you to film in different locations.  If you take the time to think it through beforehand, you can build a modest setup for about fifty bucks or less, and for something large that you can film some scenes in a movie with, you can easily set up a bigger screen for around $100 if you choose your material wisely.

The price is not only going to depend on the type of materials you choose for your green screen backgrounds but of course how much of it you need to achieve the kind of shots you’re looking for.  If there’s going to be a lot of action in your video and your actors are going to be moving around a lot and your camera is going to have to pan to follow them in-frame, you’re going to need a bigger green screen to cover that shot, which will cost more money to build.  On the other hand, if you’re shooting something like a talk show and your subjects will just be sitting on the set like good little dolls, then you’ll probably only need a small or medium size chroma key green screen, which won’t cost you as much for the building materials.

Another way of looking at this: if you’re going to just mess around with your chromakey green screen for fun and want to shoot some simple keyed video for the web, you’ll probably be setting up a smaller screen that you’ll be able to pull together for under fifty dollars.  If you’re a filmmaker who’s filming a serious movie project, you’re almost certain to need a larger chroma key background, which carries it’s own implications: for massive screens, you’ll probably paint the walls of a big room in chromakey green.  Modern movies with keyed scenes are shot in massive rooms known as “cycloramas” with rounded walls painted green and dozens of lights perfectly lighting each square inch of the screen evenly.  These would be a joy to film in, but, assuming you don’t have the budget to rent one of these studios, you’ll likely employ a more modest solution.  So in addition to your budget, the kind of videos you shoot with your green screens will factor into any intelligent selection of material to use for your green screen backgrounds.

 

chromakey green cyclorama Green Screen Backgrounds Materials Comparison

 

I’ll tell you that the most common materials used by amateur filmmakers who are serious about having good results are chromakey green muslin sheets and painted walls.  These light the best and provide the most flexibility in the specific scenarios they’re used.  Professional photographers and filmmakers typically use a combination of these, only in much larger dimensions because they have need and the budget to do so.  The people on a super budget use the ever-popular poster board and bed sheets and typically have mediocre results.  This is not to say you can’t create great looking keyed video by using these materials–you can: it just takes more effort, time, and planning with these lower end materials.

My advice is to explore your options before you pick a material for one of your green screen backgrounds.  If you just do a little research to familiarize yourself with what your needs are and what you have available to you instead of jumping straight into using the first solution that comes to mind, I guarantee you’re going to end up with a much cheaper, much better looking, and more functional result.  So familiarize yourself with your requirements, plan accordingly, and then execute.

Alright, now get out there, construct your green screen backgrounds, set up your green screen lighting properly, and get filming and photographing!  Talk to you soon. -David Carthage

 

Technorati Tags: , , , , , , , , , , ,

Posted in green screen backgrounds | Tagged , , , , , , , , , , , | Leave a comment