Histogram Node:

The Histogram helps you visualize how the individual pixel RGB values are distributed across the image.
Every pixel in an image is assigned a color which has been produced by some combination of the
primary colors red, green, and blue (RGB). Each of these colors can have a brightness value
ranging from 0 to 255 (assuming we are working with 8 bit images).

Input Range Sliders:
Shifts the “bias” of an image’s color. For example,
you can move the middle slider in the top
set to affect the bias of the midtones of the image
towards shadow or highlights. The result is an overall
darker or lighter image.

Output Range Sliders:
If your project requires calls for no blacks below
an rgb value of 10, you can remap the darkest
value to 10 by dragging the black slider to the right.

Grade Node:

White/ Blackpoint: Sets the white and black points of the image.

Lift: Uniformly lightens or darkens an image.

Gain: Adjusts the highlights of the image.

Multiply: Multiply' a channel’s values is to times them by a given factor, which has the effect of lightening
the channel while preserving the blackpoint. (This operation is similar in effect to gain.)

Offset: Uniformly lightens or darkens an image.

Gamma: Adjusts the midtones of an image.

Color Correct Node:

The Color Correct Node allows you to discreetly adjust the saturation, contrast, gamma, gain and offset of an image.

Saturation: adjusts the color intensity.

Contrast: Adjusts the brightness range found in an image. The difference between the highest and lowest luminance values.

Gamma: Adjusts the midtones of an image.

Gain: Adjusts the highlights of the image.

Offset: Uniformly lightens or darkens an image.