Image Adjustments
Auto White Balance
Auto White Balance command automatically adjusts the black point and white point in an image. This clips a portion of the shadows and highlights in each channel and maps the lightest and darkest pixels in each color channel to pure white (level 255) and pure black (level 0). The intermediate pixel values are redistributed proportionally. As a result, the usage of Auto White Balance tool increases the contrast of an image as the pixel values are expanded (unlike being compressed, as in lower contrast images). As Auto White Balance adjusts each color channel individually, it may remove color or introduce color casts.
Auto White Balance gives good results in certain images with an average distribution of pixel values that need a simple increase in contrast.
To use the Auto White Balance command: Choose Image > Adjustments > Auto White Balance.
Auto Contrast
Auto Contrast command adjusts the overall contrast and mixture of colors of RGB image automatically. As it does not adjust channels individually, Auto Contrast does not introduce or remove color casts. It clips the shadow and highlight values in an image and then maps the remaining lightest and darkest pixels of the image to pure white (level 255) and pure black (level 0). This makes the highlights appear lighter and shadows appear darker.
Auto Contrast can improve the appearance of many photographic or continuous-tone images. It does not improve flat-color images.
To use the Auto Contrast command: Choose Image > Adjustments > Auto Contrast. The application of Auto Contrast is automatic with this option.
Auto Color
Auto Color command adjusts the contrast and color of an image by identifying shadows, midtones, and highlights of an actual image.
To use the Auto Color command: Choose Image > Adjustments > Auto Color. The application of Auto Color is automatic with this option.
Auto Enhance Colors
Auto Enhance Colors filter runs an automatic saturation stretch for the image on three channels. It makes it within HSV color space, preserving hue.
For each channel of the image, this tool finds the maximum and minimum saturation values and stretches the histograms to the full saturation range.
To use the Auto Enhance Colors command: Choose Image > Adjustments > Auto Enhance Colors.
Levels
The Levels command let the the user correct the tonal range and color balance of the image by adjusting intensity levels of image shadows, midtones, and highlights. The Levels histogram is a visual guide for adjusting the image key tones.
The outer two Input Levels sliders map the black point and the white point to the settings of the Output sliders. By default, the Output sliders are at level 0, where the pixels are completely black, and level 255, where the pixels are completely white. So, in the default position for the Output sliders, moving the black input slider maps the pixel value to level 0, and moving the white point slider maps the pixel value to level 255. The remaining levels are redistributed between levels 0 and 255. This redistribution increases the tonal range of the image, in effect increasing the overall contrast of the image.
The middle Input slider adjusts the gamma in the image. It moves the midtone (level 128) and changes the intensity values of the middle range of gray tones without dramatically altering the highlights and shadows.
Choose Image > Adjustments > Levels
Brightness/Contrast
Brightness/Contrast command let the user make simple adjustments to the tonal range of an image. Unlike Curves and Levels, which apply proportional adjustments to the pixels in an image (nonlinear adjustment) based on user's settings of black or white points or the gamma, this command makes the same adjustment to every pixel in the image (linear adjustment). The Brightness/Contrast command is not recommended for high-end output because it can result in loss of image details.
To use the Brightness/Contrast command: Choose Image > Adjustments > Brightness/Contrast.
Dragging to the left decreases the level, to the right - increases it. The number on the right side of each slider value displays the brightness or contrast value. Values can range from -100 to +100
Gamma
Gamma command provides with ability to edit the gamma values of the image
To use the Gamma command: Choose Image > Adjustments > Gamma
Hue/Saturation
Hue/Saturation command let the user adjust the hue, saturation, and brightness of a specific color component or simultaneously adjust all the colors of an image.
To use the Hue/Saturation command: Choose Image > Adjustments > Hue/Saturation.
Desaturate
Desaturate command converts a color image to a grayscale image in the same color mode. For example, it assigns equal red, green, and blue values to each pixel in an RGB image to make it appear grayscale. The lightness value of each pixel won't be changed.
Channel Mixer
Channel Mixer modifies a targeted (output) color channel using a mixture of the existing (source) color channels of the image. Color channels are grayscale images which represent the tonal values of the color components of an image (RGB).
To use Channel Mixer: Choose Image > Adjustments > Channel Mixer.
Posterize
Posterize command let the user specify the number of tonal levels (or brightness values) for each channel in the image and then maps the pixels to the closest matching level.
To use Posterize command: Choose Image > Adjustments > Posterize
Invert
Invert command inverts the colors of the image. The user can use this command as a part of the process to make an edge mask for applying sharpening and other adjustments to selected areas of the image.
To use the Invert command: Choose Image > Adjustments > Invert
Invert Luma
Invert Luma command inverts the luma in the image. The user can use this command as a part of the process to make an edge mask for applying sharpening and other adjustments to selected areas of the image.
To use the Invert Luma command: Choose Image > Adjustments > Invert Luma
Histogram Equalization
Histogram Equalization command redistributes the brightness values of the pixels of an image so that they more evenly represent the entire range of brightness levels. When the user applies this command, PhotoImpro finds the brightest and darkest values in the composite image and remaps them so that the brightest value represents white and the darkest value represents black. PhotoImpro then attempts to equalize the brightness i.e. distributes the intermediate pixel values evenly throughout the grayscale.
To use the Histogram Equalization command: Choose Image > Adjustments > Equalize
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