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Click on the Plot Eyedropper and click on one of the stray pixels. In your color range sliders, a red line appears in each of the channels. You see that the line in the Y channel seems to be lurking in the softness falloff. Grab the cyan line just to the right of the red plotline and drag so that the red line falls between the two cyan lines in the Y- channel. The pixels become transparent. [an error occurred while processing this directive]
OK – Thin shirt. Click on the Matte mode for the Keyer. This brings up a histogram of the matte.
Drag the white triangle below the histogram to the left (don’t grab the white triangle at the bottom, which represents the white output of the matte – that’ll just drop the white value of the image overall). Dragging to the left begins to incorporate gray values in the matte into the white areas. Everything to the right of that cursor becomes a 255 white.
The shirt is now a solid white.
The key looks even better now, but we have some pretty hard edges with some spill.
Toggle the shrink, erode, and blur buttons.
The defaults seem to work fine for this image. Shrink actually removes pixel information around the edge of the matte. Sometimes this can get a little carried away, especially around details like fingers and such. Erode drops the value of the pixels on the edge of the matte, making them more transparent. Blur just softens the edges by adding either a Gaussian or Box blur to the edge pixels. Adjust each of the values to balance how much of the edge is lost versus how much detail you need to retain.
OK – 80% there
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| Click on image to view QuickTime Movie |
Except for a smidge of blue spill.
Change to the Color Mode and click on the eyedropper next to Color Suppression Target. Then click on the blue spill (in this image its really kind of magenta spill caused by a blending of the blue in the screen and the reds in the fleshtones – but aggravating none-the-less). This chooses the color you wish to suppress.
Use the Plot eyedropper to choose approximately the same color that you chose for your Suppression Target. This will place a line in the color histogram where your chosen color falls.
Make sure that “Supp” is highlighted. Place your cursor over the intersection of the red plotline and the white suppression curve (well, line right now, but it will soon be a curve). Your cursor becomes a cross. Click to create a bezier point on the curve and drag down. The value of your Target Suppression color changes to grays. Still looks a little ugly, and will need noodling, but better than and less perceptible that the magenta we had.
In the same method, we could shift our target color to a specified hue – either the flesh tone of the hand, or possibly the green of the BG.
Now our matte looks pretty decent. There are some areas in the rapidly moving hands where the matte is eaten away too much. There is also some spill issues present in the motion blur.
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| Click on image to view QuickTime movie |
Some of this can be finessed within the same keyer. Others may be finicky enough to require making a selection of the trouble area and placing a different keyer on it. But we have gotten to about 90% of the way there without to much trouble.
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