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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 don't 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 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 Chroma key 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 Green screener 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 Chroma key software because to try
and even this out in your Chroma key, you have crank up the tolerance a lot more and
that means going to loose edge detail, you lose detail on hair and on semi-transparent
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, 5 foot.
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 aluminium reflector here and the two tubes comes in under £60. I have got two of these units
and combined that means £120 it is less than half the price of one of these 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
we would want it green everywhere in the 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 we now have a
got a much better green screen or Chroma key lighting system.