Chroma Keying in Photoshop
Chroma keying is typically used to replace a background that is too difficult to travel to or too hard to create in a studio. Movies are not the only formats that use green screens, as these can be very useful tools in photos. Photoshop has its own feature to use the green screen or chroma keying effect. This can be used to easily change the background or to make a really interesting background for portraits.
Step 1: Color Range
Open up the photo that used the green screen as the background. The easiest way to change out the green screen is by using the color range features. The following settings need to be set with the color range tools:
- have the radio button selected
- use grayscale in the selection preview
- ensure that the invert checkbox is selected
- ensure the slider for fuzziness is set at around 30
Step 2: Select the Color
Click a green spot on the green background. With the picture changed to grayscale, the green will be a white color and the rest of the image black. If there are some green areas that are not highlighted, then hold down the shift key and click on those spots. Many times these areas will not initially be highlighted because they may be a different green shade.
Step 3: Select All Green Areas
If some of the white areas and pixels are not selected, then it may be necessary to lower the slider setting on fuzziness. Clicking and dragging the mouse key while holding the shift key down can also help. If you need a lot of accuracy, then zoom in to the different areas by pressing the control and plus buttons and then selecting all the necessary spots.
Step 4: Select Background Layer
Before removing the color, ensure that the background layer is selected. The layer that will contain the green should be changed to the normal layer. Once it is selected as normal, then invert this layer under the select menu. Hit delete, and then the green colors that have been selected will be removed.
Step 5: Halo
Many times, the person or object may still have a bit of a halo around them. The edges can be cleaned up in the layering menu by using mattes. The different mattes that can be used include the defringe matte or remove white matte. Normally setting the pixels from 1 to 3 can easily take care of the halo effect.
Step 6: Insert Background
Now that the object has been cut out, it is possible to insert the new background as a new layer that is behind the current layer with the object or person.
A Few Tips
To get the best chroma key effect possible, try to make sure that the green screen background is uniformly lit. Any shadows or different shades of green will make selecting the background color for replacement difficult. When taking a picture, make sure the RAW setting or JPEG compression is set at the maximum setting. Also experiment with some of the different settings within the Photoshop software to get the best effect. There are many tools that can be used to get a fantastic final picture.