Whilst on my various experiments with green screen work, there was a problem that came up again and again and that was the quality of the lighting.
Now I don’t mean that it was very bad, I mean that it was uneven. No matter what I did with my two 200w florescent studio lights I couldn’t get a really consistent level of light, there would always be some form of hot spotting occurring. Now whilst this looked OK to the naked eye, it really showed up in after effects when using the keylight chroma key plugin, or in fact almost any chroma key plugin.
This could be over come by cranking up the tolerance in the chroma key software but then the fine details were eroded and the edges easily lost. This is a pain as you have to record the video, then check it in after effects each time to see if your getting the hot spotting, then go back a re-adjust to try and get it right. You only need a small adjustment to make a big difference, so this can mean a lot of to-ing and fro-ing.
Then I came across and app for the iPhone/iPad from a company by Hollywood camera work called Green Screener which showed the levels of light on a green screen background and, hey presto you could see the problem much more easily before every getting near a computer or chroma key plugin.
This did allow me to get a better, more consistent lighting with the two florescent studio boxes it also highlighted an inherent problem in fact whilst the lights were bright enough, the light area is just too small and concentrated and it needed to be spread over a larger area to get the more evenly lit back ground that I was looking for.
I have already spent a bit on lighting so I wasn’t ready to commit to another lump of cash for more lights when all i needed was a more spread out light. I have seen the very large soft boxes which photographers use but I didn’t want to get these in case they didn’t work well and they are also large and I have a small home studio. Another way was needed and, in fact it has been in my ceiling all the time.
In this video I show how I used normal ceiling lights which with high frequency electronic ballasts and daylight balanced tubes to make a lighting system for the green screen which was not only a quarter of the price of my current lights but also had a much better even output of light.
The Green Screener app by Hollywood Camera work mentioned in the video is available from the Apple store here https://itunes.apple.com/gb/app/green-screener/id604935529?mt=8
Do you struggle with green screen lighting like this guy because if you i have something you need to know, stay tuned to find out.
One of the biggest problems with doing green screen or chroma key work is to make sure that the light behind you is even on the green screen because even with the best green screen material, if you dont have an even light, it ain’t going to work well. But there is a way you can do it, it can cost as little as a few dollars, it produces a good even light and it works better than a lot of standard studio lighting like this and best of all it also works really well on white backgrounds.
Now even with a really good green screen and this is a muslin material which stretched out and it has all creases pulled out of its a really nice and smooth you need good lighting and even lighting to give you a good key. Now I’m using these lights here at the moment, these are standard studio lights and as you can see the fluorescent tubes mounted in the studio by boxes.
Now that looks like it’s producing a really good key but actually we need to see how this looks on the chroma key software or something which can see what the chroma key software will see, to see what it really looks like.
Now in order to see what your chromakey software is going to see, you need something which is far more sensitive than your eyes and here we have an app for the iPad and the iPhone and is called Greenscreener and is by of a company called Hollywood camera work. Now what this does is it looks at the green screen using the camera of the actual mobile device and it will then show what it sees as the levels of light and colours these and ideally what you want is the whole thing to look completely green and what we got here is we got to hotspots of green and that’s caused by the two lights and you can see that is an uneven lighting pattern and this is going to cause a problem in your chromakey software because to try and even this out in your chromakey, you can crank up the tolerance a lot more and that means going to loose edge detail, you lose detail on hair and on semitransparent materials. You may end up doing them more and more masking and multiple keying.
So to try and get this lighting right in the first place is really very important this got me thinking that studio lights do actually do a good job but they just not tall enough and not long enough, you can see here this is the length or the actual height of the actual green screen, it needs to be much deeper and it needs be a better more even coverage .
So it got me thinking what can you use that has a good even lighting output that is not going to be another set of expensive lights and I think I found the answer. So this is what I have come up with, it is basically a ceiling light which is mounted on a studio standard lighting stands. Now as you can see this is actually a 5 foot length tube so it’s much longer and buts got a much more even throw of light from top to bottom. These things are available really cheaply sometimes they even throw them out in to skips when they’re refurbishing factories and buildings and shops so they are easy get hold of.
If you can’t find one second hand you can buy them new really cheaply but there are couple of things or recommend you get rather than just the cheapest possible thing from the hardware store. Now one of the things I would recommend is actually get these type of tubes, these are daylight balanced tubes they produce the 5300 Kelvin light output and these are made by Philips and called Master Graphica and these are the 950 in 58 watt. Now the thing about these is they will produce a balanced light which matches then the rest of the studio if you are using daylight balanced lighting equipment they don’t have to worry about inconsistent lights.
Normal fluorescent tubes, normally run around about 4400 Kelvin or lower, so that means you’ll get a mix of lighting and you don’t want that when you actually try to keep a consistent balanced lighting setup in your studio.
Now when it comes to the actual light fitting there are two types, there’s the normal ballast types which run on the mains and run at the mains frequency and then there are the electronic ones. This one is actually an electronic one they look exactly the same for the outside the only difference is that ballast unit inside is either electronic or it’s just a normal coil based one.
If you’re using the normal ones then the output from the tubes ,will have a perceivable flicker at the mains frequency of 50 or 60 Hz. Now you might not see with your own eyes that the camera can certainly see it and it can be picked up if you use a different frame rate. In the UK you need to use 25 or 50 frames per second, in the US and other parts of the world you would need to be 30 and 60 frames per second to stop any visible flickering or hum bars appearing on the actual video output.
Now if you want to run at 24 frames per second for example and a lot of people like to do that, then that’s the cause problem because if you’re using the normal ballast type ones you will get this difference bar affecting on your video output.
This is where the electronic ones come in. These run at 30,000 times a second so there is no perceivable flicker to your eye or to the camera so that what i would
recommend you use an electronic one and the tubes rather than just the normal ballast one.
Now as I say you can pick these things up cheaply if you’ve got somewhere where there may be doing a refurbishing and you want to use just the normal ballast ones but i would recommend you try and get hold of the electronic ones and it probably means you don’t have to buy a new one.
Now this whole set up including the actual electronic ballast fitting, the reflector, the only reflect here and the two tubes comes in under £60. I have got two of these units and combined that means £120 which is less than half the price of one of the studio lights.
The only other thing I added to it is a little metal bracket which I got from a hardware store and effectively bolted on the back there like that. I got my studio lighting stands which is my normal lighting stand i had anyway. There is a hole drilled in it and it literally just drops onto the top, there like that and put a nut on top there to stop it coming off and there we are. So now lets see how this works in comparison to the studio lights on the Green Screener app.
So lets see the difference, we got the strip lights now mounted on the stands and they are lighting up the green screen. Immediately even if i stand out of the way you can see the green screen looks a lot better but look at the actual Green screener app. You can really see the difference here this is no big hot spotting to either side here literally you have complete band right the way across here. It’s much better green screen that will key much better than the last one you won’t have to crank up the tolerance trying get that edge of a green screen really even.
Now you can get away with more detail and on hair and transparencies and just a better key all the way around that this is the sort of thing we’re looking for really and ideally with one it green everywhere in the green sceener app but really the difference between that and that is very very minimal and that going to work very well.
So for something which costs less than half the price of one studio light with have now got a much better green screen lighting system.