Photoshop Greenscreening

Photoshop_Greenscreen_PulpD.jpg
"Compositing" is the process of combining elements of two or more images to create a "believable" NEW image.
The process has been used in Hollywood for decades - Photoshop makes it easy to composite photos in the classroom.
Creating BELIEVABLE Greenscreen composites however, is a bit of an art. You have to be a SKILLFUL photographer and digital editor to make the illusion convincing!

Note - GREEN is only used because it is a unique and easily identifiable colour - ANY colour (including white or black) can be used in this technique, so long as it is DISTINCT from the colours worn by your subject.
Here's the Step by Step spelled out for you




STEP 1 - GET THE PICTURES
  • Match the CAMERA ANGLESand FRAMING of your SUBJECT with your BACKGROUND
    • Watch where the horizon crosses your photos
    • Keep the tripod on a similar "tilt" for both shots
    • Be sure to include your subject's feet if they should appear in the composite
  • Match the LIGHTINGof your SUBJECT with your BACKGROUND
    • Observe the location and strength of the lighting in your background shot
    • Duplicate the light angle and "softness" of that light in your greenscreen SUBJECT shot

WHITE BALANCE your GREENSCREEN CAMERA
Whitebalance01.jpg
The EXTREME GREEN in the greenscreen area tends to mess up the "Automatic White Balance" most cameras.

To OPTIMIZE the colour quality of your images, you should learn to perform a WHITE BALANCE on your particular camera. (The screen and videos on this wiki are for Canon cameras)
Whitebalance02.jpg



Once you have the shots - these steps can help you put it all together:
PREPARE YOUR IMAGES
  1. OPEN THE PHOTOS
    1. The "Subject" will be the greenscreen photo, the "Background" should match the angle and lighting to be effective
    2. The two images should appear side by side in the thumbnail display at the bottom left of the screen
  2. SELECT the SUBJECT
    1. Use the MAGIC WAND Selection Tool - set the OPTIONS at the top of the screen:
      1. Tolerance can be set between 32 and 60
      2. Antialias should be ON
      3. CONTIGUOUS should be ON
      4. Sample all layers should be OFF
    2. Click on a patch of green to select it
      1. SHIFT-CLICK to add to the selected area until you have it all
      2. Use the Magic Wand, Lasso, Polygonal lasso and Magnetic Lasso selection tools to "clean up" your selection:
        • To add more pixels to the selection - Hold SHIFT
        • To REMOVE pixels from the selection - Hold the ALT key
    3. Use SELECT - INVERT to now select the subject, rather than the background
GreenscreenMatt01.jpg
MERGE YOUR PHOTOS
  1. DRAG the SUBJECT to the BACKGROUND
    1. Use the MOVE tool (top left in the toolbox) to drag the subject onto the background (Name the new layer appropriately)
    2. Use MOVE tool to SHRINK the foreground subject to fit background. NOTE: Zoom OUT if you need to see the edges of your subject
GreenscreenMatt02.jpg
DEFRINGE the GREEN EDGES

  1. FEATHER the EDGES
    1. CTRL-CLICK the ICON of your subject layer (the little picture in the layers palette)
    2. Use SELECT-INVERSE to select the area AROUND your subject in that layer
    3. Use SELECT-FEATHER and try a feather of 1 pixel
    4. Use Ctrl-H to HIDE the selection borders
    5. Hit the DELETE key to "eat away" the bordering pixels and see if that makes the image look more or less believable - repeat if necessary
    6. Hit CTRL-D to deselect the "invisible" selection area
  2. RECOLOUR the GREEN
    1. Create a new layer above your SUBJECT layer
    2. Set it's LAYER MODE from "normal" to "COLOUR"
    3. CTRL-Click the layer icon for your subject to create a selection (but stay on the new "colour" layer)
    4. Use the CLONE STAMP tool
      1. Be sure that USE ALL LAYERS and ALIGNED options are turned on
      2. Choose a decent sized brush for the job
      3. ALT-Click a GOOD colour from the interior of your subject - let go of the ALT
      4. Paint the outer fringe with appropriate internal colours.
      5. WHEN COMPLETE - you can use the Layers Palette Menu and MERGE DOWN to "fix" the colours permanently.
GreenscreenMatt03.jpg


ENHANCE THE ILLUSION
  1. ADD FOREGROUND ELEMENTS
    1. Select elements from the background that you'd like to place in FRONT of your subject and use Ctrl-J to put them in their own layer.
    2. Drag that layer above your subject's layer to add realistic immersion

  1. ADD SHADOWS
    1. Create a layer under the subject. You may also copy the layer, flip it vertically, and re-colour it to appear as a shadow.
    2. Use a brush and paint appropriate shading.
    3. Change the layer opacity to between 30% and 70% to create believability
GreenscreenGiant03.jpg