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How to recombine colour channels with GRIP

This technique requires 3 photos which have been taken with a fixed camera and manual settings. The idea is to have a fixed background against which something moves or changes in some way. Typically the 3 photos would have been taken in fairly rapid succession as the motion or change occurs. Automatic camera settings might not produce quite the same background in all 3 pictures, so manual settings kept the same throughout the sequence are recommended.

  1. Fix the camera and use manual settings to take three photos.
  2. Open all 3 images in GRIP by using the Open option on GRIP's main File menu. The images will be in 3 separate windows with their own menus.
  3. If the images were taken in RAW mode see how to open RAW images.
  4. If GRIP's main window is hidden by image windows bring it to the front by typing Ctrl-G.
  5. On GRIP's file menu select "List and select images". A new window will be displayed, containing a table of all the images which are now open. This window has its own menu bar.
  6. Select all three images in the table. This can be done in various ways:
    • Hold the Shift or Ctrl key down and click on each row in the table.
    • On the table's Edit menu, choose "Select all" (assuming only our 3 images are open).
    • Type Ctrl-A (assuming only our 3 images are open).
  7. When exactly three images have been selected, the table's Combine menu will show that option "Recombine channels" is available. Selecting this option cycles the red, green and blue channels among the 3 images. If image 1 was originally made up of channels R1, G1, B1 and image 2 was R2, G2, B2, and so on, the 3 images are changed as follows.
    • R1 G1 B1 → R1 G2 B3
    • R2 G2 B2 → R2 G3 B1
    • R3 G3 B3 → R3 G1 B2
  8. Save whichever result is pleasing enough to keep, by using the "Save as" option of the Image menu of that particular image.
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