Using the new color corrector of 3.1 to suppress a color can be quite useful when your footage has undesired elements. It will selectively remove a color from the footage, leaving the rest of the spectrum. But what if the color doesn't quite fit into one of the 6 suppression slots? No problem. In the following example I will show you how to deal with this.

Requirements: Digital Fusion 3.1 or higher, DFX+
Flow: N/A
Images:  Download the Targa. (1.2 meg)
Archive:  Printable Microsoft Word Document. (1.5 meg)

For this tip, please save the above Targa file to your hard drive.

1. Set up a basic flow with a loader, and a color corrector.
2. Load the  included targa file.
   
   
   
   
   
3. Enter the suppress mode of the corrections tab and drag the red slider all the way down.
   
   
   
   
   
   

Now as you can see, the red of the roses and strawberries is still visible. This is because the colors don't fit neatly into the pure red spectrum. To fix this, do the following:

4. Go back to the colors mode of the correction tab.
5. Adjust the hue offset to bring more of the magenta into the true red spectrum. A value of about 0.12 is good.






6. The result.
7. Now we have to put the image back to its normal hue. So we add a second color corrector, and enter the inverse of the hue offset from the first color corrector. In this case it's -0.12
   
   

As you can see, by picking the slot that is closest to the color you are trying to suppress and adjusting your hue offset in small increments to get it "just right," you can minimize if not eliminate the unwanted colors. I suggest using the numeric inputs, and hovering your pointer over the desired area to make sure the RGB values are as neutral as possible. If you want to remove all the color from the roses and strawberries try minimizing the magenta slider as well.

This technique can be quite useful when dealing with blue or green screen materials. It may be possible to swing the green or blue to a pure chroma, or even help remove those stubborn fringes caused by 4:1:1 formats.