Tools > Color > Adjust Colors (applicable to a point object that has vertex color, and to a polygon object that has vertex color or texture color) is a set of functions that modify the color of all points or pixels of the active point or polygon object. This is like adjusting the brightness on your television.
Adjustment dropdown - The choices and the choice-specific controls are:
Brightness/Contrast - modifies the numerical brightness and contrast values.
Brightness slider (-1.0 to 1.0) - Negative 1 equates to solid black, positive 1 to solid white.
Contrast slider (-1.0 to 1.0) - Negative 1 equates to no contrast (features are indistinguishable); positive 1 to maximum contrast (too much glare).
Gamma Correction - controls the brightness of the object in logarithmic way. It serves to correct the exponential characteristic of CRT monitors.
Channel (all channels, red, green, blue) - specifies the color channel whose gamma setting will be adjusted.
Gamma indicator - indicates the setting of the Gamma slider.
Gamma slider and graphical representation (0.2 to 4.0) - adjusts the gamma setting
RGB Correction - modifies the levels of Red, Green, and Blue on the active object.
Red indicator - indicates the setting of the Red slider
Red slider (-1.0 to 1.0) - adjusts the level of red
Green indicator - indicates the setting of the Green slider
Green slider (-1.0 to 1.0) - adjusts the level of green
Blue indicator - indicates the setting of the Blue slider
Blue slider (-1.0 to 1.0) - adjusts the level of blue
HSL Correction - modifies the numerical Hue, Saturation, and Lightness levels on the active object.
Hue indicator - indicates the setting of the Hue slider
Hue slider (-180 to 180) - adjust the hue
Saturation indicator - indicates the setting of the Saturation slider
Saturation slider (-1.0 to 1.0) - adjusts the color saturation
Lightness indicator - indicates the setting of the Lightness slider
Lightness slider (-1.0 to 1.0) - adjusts the lightness
Posterize - reduces the number of distinct colors to a specific number.
Levels indicator - indicates the setting of the Levels slider.
Levels slider (2 to 256) - reduces the number of distinct colors to a specific number
Histogram - adjusts the contrast of the object. The graphical panel shows the number of texels that have a given intensity.
Low slider (the range is "low" to the current setting of the High slider).
High slider (the range is the current setting of the Low slider to "high").
Stretch button - modifies the intensities between the two limits by linearly stretching them along the full range.
Equalize button - transforms the histogram to get similar frequency for along the whole range, that is, it tries to distribute the intensity values equally.
Grayscale - converts all colored points or polygons to shades of gray.
Negative Image - inverts the RGB components.
Display Control group - controls the appearance of the object in the Viewing Area.
Interactive checkbox - causes all adjustments to appear in real-time, as opposed to becoming visible only when a slider button is released. Typically, leave this turned on.
Disable Lighting checkbox - deactivates the artificial light source.
OK button - saves adjusted colors to the object in the Model Manager and closes the dialog.
Cancel button - terminates the dialog without saving adjustments.
Reset button - restores settings that existed when this function started.