Hey, want to learn a magic trick? Here’s one: how would you like to transport yourself from Paris, France without ever getting on a plane? Okay, so you won’t actually get to go to Paris (sorry!) and it isn’t really magic, it’s chroma key–a green screen–but it’s still a pretty awesome skill to learn. You have probably heard of green screen before; it’s most commonly used in movies to insert an actor or computer generated asset into the scene. It’s especially helpful for recreating scenes that are out of reach financially, logistically, or realistically. After all, lots of movies take place in fantastical landscapes that don’t even exist; a barren planet, for instance, or a fairy-tale forest. Chroma key isn’t just for movies, though. You can learn green screen photography techniques that you can then bring into Photoshop so you can create your own backgrounds for ordinary, everyday pictures in order to transform them into something a little less ordinary. Maybe even magical!
Understanding Chroma Key
The “green screen” is actually just a layman’s term for chroma keying, which is used to layer–or composite, if you want to impress your friends–two video streams or pictures together. You can use pretty much any uniform background for chroma keying, which is why there are “blue screens” in addition to green ones. The reason you need something uniform and preferably easy to distinguish, like a neon green, is because you will select all of that color on one layer and delete it. That’s why weather forecasters have to stay away from green or blue–otherwise you’d end up with a torso-less, disembodied meteorologist.
In addition, green and blue are considered to be the furthest hues away from skin tone, so there’s no danger of accidentally lopping off an earlobe.
Now that you know a little bit about why green screen is used, let’s get started. The first thing you will need to do, obviously, is get a picture in front of a green screen.
Making and Lighting A Green Screen
Chroma key is used for lots of different things, as you already know. So the first thing that you will need to do is to make a green screen and photograph the image that you would like to manipulate. For our purposes, let’s use the example above and send you to Paris. That means that you are the subject of the photo. Say, “fromage”!
You don’t need to spend a lot of money to make or set up a green screen, although there are certainly options for that if you want to. Since we know you’re anxious to get to Rue De Rennes, though, we’ll go the the speedy route. Here’s what you need.
- A big piece of neon green or otherwise loud, green fabric, about 5’X5′
- A whole bunch of thumbtacks or gaffer’s tape
- Big, bright lights
- A Camera
Here’s how to set up your shot:
- Hang the fabric. We went big to give you a bigger backdrop to work with, but don’t be too concerned if it isn’t exactly measured. You can even get large pieces of bright green poster or foam core board that will do the trick nicely, just be sure to seal any seams with green tape if you’re using more than one piece.
- Keep in mind that you want a uniform background, so that means as wrinkle- and crease-free as you can get it, which can be tough with fabric. This is where your fasteners like thumbtacks or tape comes in. If you’re not keen on the idea of putting holes in your wall, try the gaffer’s tape. It comes off easily, you can get it in bright green, and it has the added benefit of making you sound like a professional.
- Light the background. This goes to uniformity and ease of manipulation. You want to avoid as much shadow as you can, so you might have to mess with the set up for awhile until you get what you’re after.
- Take the picture. Since you’re the subject, have a friend help you or take a selfie. The picture needs to be digital, obviously, since we’re taking it into Photoshop, but iPhones actually have some pretty great photography tools built in.
Know Your Lingo
If you are new to Photoshop, never fear! We will quickly go over some Photoshop tools and terms that are helpful to know, but you can rest easy in the knowledge that green screen Photoshop image manipulation is one of the easiest things you can do. If you’ve been wanting to explore Photoshop for awhile but were unsure of where to begin, this is a perfect project to cut your teeth on.
Layer-A layer is an image. You can add lots of layers into your Photoshop project and then work on them one at a time by clicking or unclicking the eye icon next to that layer (now you see it, now you don’t).
Crop-The crop tool helps you cut out junk on the borders of your picture or isolate a more detailed image. It looks like a diagonal diamond connected with hatch marks in the corner. When you mouse over your tools in the sidebar, it will say “Crop tool”.
Color Range- Color range is a command, as opposed to a tool. You can find it in the “select” menu, and it allows you a greater range of color selection than the magic wand.
Eyedropper– You’ll recognize this, because it looks just like an eye dropper. You can use it to make a very specific color selection in the color range command so that you can isolate that color. Do you see where we’re going with this?
There are so many tools in Photoshop, and it is easy to get overwhelmed when you see them all lined up without any context regarding their use, but don’t let that put you off! The tools and terms above represent the range of what you will need for green screen Photoshop projects, and they’re good to know for future projects, too!
Let’s Do This
Before you get started, go ahead and choose a background photo that you like, for our purposes, let’s say the Eiffel Tower. You will use this to replace your green screen. Name it with an easily recognizable name.
- Get the photo you took onto your computer. Depending what camera or method you used, how you do this will vary, but get it uploaded and name it something that you will recognize.
- Open Photoshop, and then click File>Open on the file menu to bring your photos up. There should be two layers. Click the eye so that it disappears next to your new background picture so that you can work on just the green screen Photoshop image.
- If you got a wide shot, and something extraneous is in the picture, like a piece of furniture, gaffer’s tape, or the family dog, use the crop tool on the side tool bar to select the part of the picture you need.
- Next, find the select menu, and click Select>Color Range to bring up your color selection tool. You will see the eyedropper tool and a selection preview window.
- Choose the eyedropper tool and drag it, while holding the shift key to select the green background. Dragging it around will grab any green hues that aren’t uniform, like a shadow or highlight. Click OK.
- While you do this, check the preview window. You should see a silhouette of the foreground image (you) in black, and the green screen should be white. If any of the silhouette turns white, use the eyedropper and ALT key to deselect those sections on the photo layer.
- Go back to the select menu and choose Select>Inverse. Now you should see white where your green screen was.
- Choose Select>Refine edge to smoothen the outline of yourself. You can play with the sliders in the preview box until you are happy with the way it looks.
- Choose Select>Inverse one more time, and delete the background by pressing backspace. Now you should see the background as a little checkerboard of white and gray. This means you’ve isolated the image of yourself.
- Click on the eye again next to the background layer. You should now see a picture of yourself in front of the Eiffel Tower! You can drag the top layer around until you have the composition you want.
- Don’t forget to save your masterpiece!
Now you know a little Photoshop magic. With an understanding of how green screen Photoshop technique and trickery works, you can do all kinds of things! If you have an online store, for example, you can use it to superimpose images of your product over nice backgrounds, or just have a little fun with your friends by posting an entire Facebook album of your “travels”. If you get really ambitious, you can even try your hand at using learning to use green screen to composite video layers together, since you already understand the basic mechanics of how chroma key works. Where to next? Prague? Tokyo? How about something a little more otherworldly, like the Moon? All you need is a green screen, Photoshop, and a camera!