To increase the probability of pulling a good key, you can modify the levels of the RGB channels, saturation and luma.

Toggle the Red, Green, Blue, Saturation, and Luma buttons to activate their corresponding curves. Manipulate the shape of each curve over the source hue range that you want to affect. The value of the parameter that corresponds with the curve changes relative to the height of the point along the curve in the curve editing area.

Each curve is a hue gradient and as the shape of the curve changes, the colors along the curve's gradient change to reflect the result. For example:

• Raising the luma curve over the green hue range, the green curve along that range becomes brighter—the luma value increases (RGB values increase together).
• Lowering the blue curve over the magenta hue range, the blue curve over that range becomes red—the blue (B channel only) value decreases.