Joe Maller: Joe's Filters: Joe's RGB Desaturate

Joe's RGB Desaturate is a part of Joe's Filters, a shareware package of utility and image processing tools for Final Cut Pro.

What it does

Joe's RGB Desaturate creates grayscale images from specific color channels. Since the Red Green and Blue channels are essentially grayscale images, there are three distinctly different grayscale files to choose from. Joe's Radial Desaturate offer additional precision controls for converting color images to grayscale.

If you are curious about FXScripts and Final Cut Pro, I also wrote a page about the FXScript behind Joe's RGB Desaturate...

Example Images

These examples show the effects of different color desaturation settings on a color video frame. Notice how generally flat the Gray desaturation is and how highly contrasted the tomatoes are in the Green desaturation. Because channels are additive (meaning they combine and get brighter) a parallel photographic filtering effect would be the inverse of the channel's color. The blue channel would be similar to shooting black and white with a yellow-orange filter. This is also why a warm-red filter like a Tiffen Red 23A will increase contrast in blue skies.

Original Image
100% Desaturate to Gray	50% Desaturate to Gray
100% Desaturation to Red	50% Desaturation to Red
100% Desaturation to Green	50% Desaturation to Green
100% Desaturation to Blue	50% Desaturation to Blue

The Controls

• Source (Gray, Red, Green, Blue)

  Chooses the source of the desaturation from the three color channels or the mix of all three. Gray uses straight averaging instead of weighted luminance averaging.

• Saturation (0 - 100%)

  This sets the amount of desaturation. Essentially this overlay's the desaturated gray image over the original at a set opacity. 100% Saturation has no effect on the image but would still need rendering.