Using chroma key techniques can open the door to creativity. Artists can use these new tools to create realistic images once only seen in his or her own mind's eye. Professional photo studios can offer their clients a greater selection of products. There is no need to keep several backdrops on hand. All a photographer needs is a nice single colored background, and with the digital chroma key process, has access to literally millions of background choices. This tutorial shows the process of removing a subject from a green background using Adobe Photoshop

Step 1: Proper Green Screen Studio Setup

Setting up your studio backdrop is a very important step to getting great images. The work you put into placing the green screen and properly lighting it will translate to an easier process in the image editing step.

Use a low-reflective surface for the green screen to keep glare to a minimum. A cloth can be used but be sure to get out all the wrinkles. An uneven surface, and unevenly lit surface will make the removal process later much more difficult.

You can also use paper or a painted surface for your green screen. Wrinkles are impossible with this setup but you still must evenly light the surface. Be sure to use a flat matte paint to reduce glare and sheen.

And finally, make sure the subject is a little brighter than the green screen. When lighting your subject, be sure not to cast shadows on the background as in the picture. Move the subject further away from the green screen.

Step 2: Digitally Remove the Green Screen

When you open your image in Adobe Photoshop (PS), go ahead and change the background layer into a usable layer. Double click the background layer in the layer window in the bottom right hand part of the screen. A new layer dialog box will appear. You can change the name or properties here if you like, then click the ok button.

To remove the green screen from behind the subject, first you must make a selection from the background. There are many ways to do this, however, it is recommended to use the color select tool. Select from the drop-down menu >Select>Color Range>. In the dialog box, be sure to select the eyedropper with the + next to it. This will allow you to select the green, along with the light-green areas and dark-green areas. With the eyedropper tool now selected, click around on the green background until you notice all of the background area become white within the dialog box. Adjust the Fuzziness slider so that all the background is white, and all of the subject is black. Then click the ok button.

You will notice the "marching ants" perimeter around your subject indicating where the selection begins and ends. Depending on the size of your image, you should apply a 1 or 2 pixel feather to the selection to be sure there are no jagged edges around your subject. To do this, select >Select>Modify>Feather> from the drop-down menu in PS. Enter the desired pixel size to feather and click the ok button.

To remove the green screen, you apply a mask to the area not selected. Since the green background is currently selected, you need to invert the selection to have the subject selected instead. Choose >Select>Inverse> from the drop-down menu. You will notice a slight difference in the "marching ants". Now you have your subject selected, not the background. Now, press the add layer mask button at the bottom of the layer window in the lower right part of the screen. If you followed the steps correctly, you should see your green background disappear. It's still there, just masked.

When you are happy with your selection, you may completely remove the green screen by applying the layer mask, making it permanent. Right-click on the black and white mask icon next to your layer and choose >Apply Layer Mask>. The layer mask with disappear and you will be left with just your subject.

Step 3: Merge the Subject and Background

Make a close selection of your subject to be sure that there are no border artifacts included along with your subject. Copy the selection to your clipboard by choosing >Edit>Copy> from the menu or ctrl+c.

Open your background image, then paste in your subject by choosing >Edit>Paste> from the menu or ctrl+v. Size and position the subject where you would like it to be in the scene.

More than likely, there will be some residual green left around the perimeter of your subject. This can be removed easily using the Hue/Saturation adjustment tool. Select >Image>Adjustments>Hue/Saturation> from the drop-down menu or ctrl+u. In the dialog box where "Master" is in the drop-down menu, select "green" and adjust the saturation slider below until you see the greenish perimeter disappear, you may also need to adjust the "yellow" depending on the color of your green screen.

Congratulations, you now have a final product. Let your creativity fly, the possibilities are endless.

Below are some Chroma Key tools that you might add to your studio setup.