How to Use a Green Screen – In-depth Guide from Lighting to Edit
In this tutorial, I’m going to show you how to use a green screen all the way from lighting it to the editing process. This is an in-depth tutorial to leave any confusion behind and ensure you get great results every time you use a green screen.
You use green screens to enable you to place people or objects into different scenes very easily. This will be a great tutorial for anyone looking to use this technique for Photoshop composites, stock photography, product photography or just to put people into different backgrounds.
Control your photography and be much more creative with it in our online courses. Click below for more details.
Synopsis of the tutorial
What are Green Screens?
Green screens are used so that you can replace the background and put any picture there. Let's start by talking to you about what you need. You’ll need a green screen in a colour that’s called ‘chroma green’. There are lots of different versions out there, but my recommendation is to get the paper roll ones because they are the smoothest, and the smoother you make your green screen, the easier it is to edit.
Lighting the Green Screen
Light your green screen. I’m using two soft boxes to spread soft light across the background evenly.
Do an exposure test to make sure the light is even across all of the background. To do this, you will need a remote trigger to fire off the flashes and a light meter to measure the light across the whole green screen.
Get the background evenly lit. Mine is around f/8 and a half across the whole background.
Lighting the model
Get your exposure right for where your model is and balance it out against the background.
Get the model to stand in front of the background lights - that's really important because you don't want the background lights to be hitting the model.
To light the model, I'm using a white brolly. This is to give me a reflected soft light that is spread quite wide. I'm doing that because I want general stock shots so I can place the model into any picture that I want.
If you are doing it for a specific image, you are going to need to look at that image and figure out where the light is coming from and adjust your lights to match.
Take a meter reading where the model will be standing. You want it to be the same or within half a stop difference from the background. My light meter is giving me f/8 which means the background is half a stop brighter than the foreground.
What you don’t want when you’re doing green screen photography is overspill; so, if the background lights are more than half a stop brighter than your foreground light, it's going to reflect back green light. If this happens, when you erase the green screen on the computer, you're going to start erasing parts of the skin and hair etc. Getting this lighting set up right first is absolutely key.
Removing the Green Screen in Photoshop
Firstly, we need to separate the green from the person.
Go to Select > Colour range > put your fuzziness to 80 or 90 > click on the eyedropper tool > select ‘sample colours’ from the drop down menu > whilst holding down the shift key click on the green parts of your picture (the background) > click OK.
Everything that's white in the box will be your selection and everything that's black will not be your selection.
Go to Select > Select and mask > In the select and mask window, under ‘view’, select ‘black and white’.
If you see any white parts within your model, select the minus brush tool and paint over these areas to remove them from the selection.
Click ‘view’ again and select ‘marching ants’.
Invert the selection. In the select and mask window, click invert > click on ‘view’ again and select ‘overlay’ so that you can see the picture a bit better.
If there is still some green around the edge of the model, tick ‘decontaminate colours’ to help remove this.
Feather the selection to make it look more natural - I did mine by 2.8 pixels. You can also add some smoothing to that edge if needed.
Go to ‘output to:’ > new layer with layer mask > click OK.
To refine the image further, add a hue/saturation adjustment layer to target specific colours and desaturate them.
Merge the hue/saturation layer with the layer that has the background removed.
Use your move tool located in your tool box, click on the person and then drag them into another picture.
Do some adjustments to make it look more natural. In my example I change the background into a smart object then I go to filter > blur > Gaussian blur.
To further edit this picture, I match the colours of the person to the background. A really good tip is to look in the highlights and the shadows of your picture. I did that using a curves adjustment layer.
Right click on this curves adjustment layer and select ‘create clipping mask’ – that clips the curves layer to just the layer below it.
And that’s how you use a green screen from lighting to edit. This picture is on the front cover of our Complete Guide to Photography book, just to show you that we practice what we preach here at TSoP.
If you've liked this tutorial, please like it and share it with your friends, subscribe to our channel and leave us a comment. If you don't do all of them things, we can't bring you these videos and we really appreciate it when you do. We also have an excellent learning community on social media so please join us there as well.
Thanks for dropping by and remember learn more at The School of Photography.