Contrast enhancement

LOCAL CONTRAST ENHANCEMENT
Local contrast enhancement attempts to increase the appearance of large-scale light-dark transitions, similar to how sharpening with an "unsharp mask" increases the appearance of small-scale edges.

Contrast enhancement - Automatically brightens images that appear dark or hazy, and applies appropriate tone correction to deliver optimal quality and clarity.

Local Contrast Enhancement Technique
What is this mystery tool: Unsharp Mask (USM) applied differently than the way it is usually used.
Figure 17: USM ...

[edit] Contrast enhancement
Filters are commonly used in black and white photography to manipulate contrast. For example a yellow filter will enhance the contrast between clouds and sky by darkening the latter.

Color-based contrast enhancement can be applied using Hue/Saturation adjustment layer in luminosity blend mode.
Sharpness
All settings at 0. Do not apply in raw conversion.

The same sort of contrast enhancement can be accomplished by printing through paper positives and negatives. The contrast enhancement can also be moderated by using films or papers of medium or low contrast and by using low- contrast developers.

As its name implies Strength controls the overall strength of the contrast enhancement effect. The maximum setting of 100% will give you good results with some images but you may need to back it off for others to avoid harshness.

NIH Image supports many standard image-processing functions, such as contrast enhancement, density profiling, smoothing, sharpening, edge detection, median filtering, and spatial convolution with user-defined kernels.

I usually don’t adjust microcontrast much. Micro contrast enhancement is similar to sharpening in Photoshop. I play with this slider in extreme cases, when I get halos or too much noise, but otherwise I do not adjust it much.

The most important mode dial position for this camera is iAuto, which combines the Live Guide simplified interface with automatic scene recognition and the iEnhance selective color and contrast enhancement feature for point-and-shoot creation of ...

The B/W Conversion: Tonal Enhancer filter has a drop-down Contrast Method menu with three options that provide three separate starting points for contrast enhancement. Color Efex also includes conversion filters that are task-specific: ...

See also: Cement, Image, Contrast, Color, Light