Photoshop Color Correction - Giordan on Graphics | 7
#9- Channel Mixer
Now this one is interesting. It lets you modify a color channel by combining the data from another channel in the file. It can be confusing though, and Im running out of space, but let me try to explain.
A channel is comprised of grayscale data representing the tonal range of the channel. This control lets you select a target channel to modify adding percentages of the other channels in the file to the target. The thing to remember here is that you are not adding the color itself you are only adding the grayscale values to the channel. For example, you can select the red channel to modify, and then increase the green channel slider. Does the image turn green? No, it turns either red or cyan. You add the grayscale values from the green channel to the red one, which makes it either more or less red, depending on whats in the green channel.
You may have an image with strong color in a particular area. Combining one color channel to another lets you balance the color in that area. Im on the fence on this one Im not sure if this is a niche control that is useful, or if its just the result of engineers doing something just because they can.