Bair Art Edition's Tutorial on:
Adjusting Color & Exposure
In Adobe Photoshop
Color Adjustment: How I Think Levels Should Be
This page does NOT reflect how Adobe Photoshop displays the Levels control panel.
This is solely a demonstration of how the author understands the levels tool, and the histograms of the individual channels. What I have done is given color values to the histogram, so the amount of information at a tonal level is also colored the same color as that value.
For the full RGB, it would look like this:
Each channel has a histogram. This graph represents the amount of information (amount of the image) that has certain values of that color. These values range from no contribution of that color, to a full contribution of that color.
This is how I see it:
Using Cyan to demonstrate the lack of Red
Using Magenta to demonstrate the lack of Green
Using Yellow to demonstrate the lack of Blue
Now Let's See What Happens When you Move the Sliders
The following will demonstrate what is, in effect, happening when you move the "white" or "black" slider in a channel.
Without moving the slider:
After moving the slider:
This shows how a predominantly Yellow-cast is subdued, and the information recorded in the blue channel is now redefined. The place where image information tapers off, is now the pure Blue point.
And this is what, in effect, happens when you move the mid-point:
I know that was an extreme shift, but as you can see, much more of the image will receive green light than did before the slide. And as a result, less of the image has Magenta values (which is, in all practicallity, the lack of Green).
The following are the sections of this module: