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Image Adjustments
Astra Image has many interactive image adjustments that can enhance your photos easily. These adjustments are in the Image Adjustments window which docks inside the main Astra Image application window.
The Image Adjustments window can be docked on either the right or left side of the Astra Image application, and it can also be hidden altogether. The options to do this are in the View > Adjustments Window sub menu.
Each group in the Adjustments window has a checkbox allowing the image adjustments in that box to be turned on or off.
Also, there is a reset button that returns all controls in that group to their default values and settings.
Please note that any adjustments made will not be permanently applied to the image until the Apply Permanently button is clicked.
Actions
The Actions group has only two options. This first is “Apply Permanently”. Clicking this button will apply all the settings in the Adjustments window to the image so that is can be saved and further manipulated. There is also an option to “View Original Image”. By clicking and holding the left mouse button, the image is displayed without any adjustments applied. When the mouse button is released, the image with the adjustments will be displayed again. This gives you a very useful before / after comparison.
Levels
The Levels group provides tools to manipulate the black, mid-tone and white points, as well as to do auto-scaling. It contains several controls and functions.
Histogram: the histogram of the image is displayed with red, green, blue and intensity channels by default. The channels displayed can be changed by the drop-down list box above the histogram. The histogram scaling and chart style can be changed by clicking the options button.
Auto Levels: 
when clicked, the image levels will be automatically adjusted. Each channel in the image is altered by the same amount. The strength of this function can be changed by clicking the Options button and entering new values for the Black clipping point and White clipping point.
Auto Colors: 
when clicked, the image levels will be automatically adjusted. Each channel in the image is altered independently. This means that good color balance can usually be automatically obtained. The strength of this function can be changed by clicking the Options button and entering new values for the Black clipping point and White clipping point.
Settings: 
as noted above, this function allows for the adjustment of the clipping points for the Auto Levels and Auto Colors functions, as well as providing different options for the histogram chart.
Black, Midtone and White Sliders: Below the histogram are three sliders which allow the black, mid-tone and white points to be adjusted by dragging with the left mouse button.
Light
The Light group contains various basic adjustments that can change the brightness and contrast of your image.
Brightness: adjusts the global brightness of the image in a non-linear fashion to try and preserve as much detail as possible.
Contrast: adjusts the global contrast of the image in a non-linear fashion to try and preserve as much detail as possible.
Exposure: adjusts the apparent exposure of the image.
Exposure Offset: allows the base of the exposure adjustment to be moved towards the black point or the white point.
Gamma: adjusts the global gamma setting for the image.
Color
The Color group allows make common color adjustments.
Saturation: adjusts the color saturation. Low values result in a more monochrome image, while higher values increase color intensity.
Hue: changes the colors in the image by the specified number of degrees. For example, blue will become red when the Hue setting is at 180 degrees.
Tint: this is similar to the hue setting, but more constrained, allowing for color casts to be easily corrected. The overall look of the image can be changed from more green (with a negative value) to more red (with a positive value).
Color Temperature: allows the global image color balance to be shifted towards either blue or red. A more advanced version of this adjustment is available in the Enhance menu item where the exact temperature of the lighting can be specified in degrees Kelvin.
Tone
The Tone group gives you adjustments for brightness constrained to specific zones within your photos, from Shadows to Highlights. This allows you to very precisely adjust the brightness of certain regions withing your image.
Shadows: adjusts the brightness in regions of the image that are very dark.
Darks: adjusts the brightness in regions of the image that are dark.
Midtones: adjusts the brightness in regions that are moderately bright.
Lights: adjusts the brightness in regions of the image that are bright.
Highlights: adjusts the brightness in regions of the image that are very bright.
Contrast
The Contrast group gives you adjustments for the contrast in specific zones of the image, from Shadows to Highlights. This allows you to make precise contrast adjustments.
Shadows: adjusts the contrast in dark regions of the image.
Midtones: adjusts the contrast in regions of the image that are moderately bright.
Highlights: adjusts the contrast in bright regions of the image.
Pixel Information
The Pixel Information group has information about the location, color and brightness of the pixel that is currently under the mouse cursor. The range of the red, green and blue readout can by adjusted by clicking the settings button.