The Filter menu contains commands for adjusting brightness/contrast; to lighten or darken an image; and to apply image maps and filters.
The Last Filter command [Command-F] is the first command listed in the Filter menu. The command changes to reflect the last filter used, and is a shortcut to apply that filter with the same settings once again.
The Adjustment command displays a menu with commands for adjusting the image for a document or selection.
The Auto Contrast command is a shortcut to improve an image by optimizing the brightness and contrast, and has no dialog box. This may be the only contrast adjustment needed to improve the image.
The Brightness/Contrast command [Command-B] also lets you adjust the brightness and contrast of an image. The command opens a dialog box with sliders. The top slider adjusts Brightness in percentages from +/- 100%. The bottom slider adjusts Contrast in percentages from +/-100%. Adjustments are made by moving the slider bar, clicking on the pointers at each end of the slider or entering a +/- percent in the textbox.
Checking the Live checkbox applies changes to the entire screen and removes the Before and After views.
The Brightness RGB command opens a dialog box similar to Brightness/Contrast, but with individual sliders for the red, green and blue channels. Adjustments are made by moving the slider bar, clicking on the pointers at each end of the slider or entering a +/- percent in the textbox.
Checking the Lock checkbox links all sliders together.
Clicking the Reset button returns all settings to their defaults.
Checking the Live checkbox applies changes made to the entire screen and removes the Before and After views.
The Contrast RGB command opens a dialog box similar to Brightness RGB, with individual sliders for the red, green and blue channels. Adjustments are made by moving the slider bar, clicking on the pointers at each end of the slider or entering a +/- percent in the textbox.
Checking the Lock checkbox links all sliders together.
Clicking the Reset button returns all settings to their defaults.
Checking the Live checkbox applies changes made to the entire screen.
The Image Map command displays a menu with commands for changing the map for a document or selection (Note that this is different from the Web Image Map).
The Invert command creates a negative of the image: white becomes black; black becomes white; 30% black becomes 70% black, etc.
The Threshold command opens a dialog box to convert the image to only pure black and white areas.
Levels below the threshold point turn black and levels above the threshold point turn white. The threshold point may be set by moving the slider bar, clicking on the pointers at each end of the slider or entering a number from 1-255 in the textbox. Checking the Live checkbox applies changes made to the entire screen and removes the Before and After views.
The Posterize command allows you to create special effects by limiting the number of color levels in the image. The number of levels is entered in the text box or by moving the slider bar, clicking on the pointers at each end of the slider or entering a number from 1-255 in the textbox. Checking the Live checkbox applies changes made to the entire screen and removes the Before and After views.
The Blur command displays a menu with several different blur commands. The Blur (1) and Blur More (2) commands apply different amounts of blur to the image.
The Noise command displays a menu with commands for adding or subtracting noise from an image. Noise is pixels of random colors scattered throughout an image.
The Add Noise command opens a dialog box. The Levels (the harshness) is set by entering a number in the textbox or clicking the up or down arrows to increase or decrease the number displayed The Area slider sets the color levels to be affected (light to dark areas); this is adjusted by moving the slider bar or clicking on the pointers at each end.
Choose the type of noise with the Uniform or Gaussian radio buttons. Uniform applies random noise along a linear distribution; Gaussian selects the values along a Gaussian curve.
The Despeckle command opens a dialog box used to reduce noise in an image. Adjust the Intensity by moving the slider bar, clicking on the pointers at each end of the slider or entering a number between 1 and 16 in the text box.
The Sharpen command opens a menu of commands that let you sharpen fuzzy images by increasing the contrast of adjacent pixels. The Sharpen (1) and Sharpen More (2) commands apply different levels of sharpening to the image.
The Stylize command opens a menu with commands for changing the visual appearance of the image.
The Mosaic command opens a dialog box that lets you group pixels into mosaic squares. The filter averages the color values of the pixels within the square and changes them all to that value. Adjust the Levels by moving the slider bar, clicking on the pointers at each end of the slider or entering a value between 2 to 64 in the text box.
The Solarize command applies an image map that changes the image by inverting the upper 50% of the colors.
The NTSC Video Safe... command changes the image to eliminate extremely dark or light (saturated) colors which do not display well on standard NTSC video devices such as televisions and video recorders.
The Compressed radio button remaps gray levels from 0-255 to 12-243.
The Cropped radio button remaps gray levels by changing all levels below 12 to 12. All levels above 243 are changed to 243.
The Other command opens a menu with other commands for adjusting images.
The Minimum command opens a dialog box where you can adjust the Intensity by moving the slider bar, clicking on the pointers at each end of the slider or entering a number from 1-16 in the textbox.
The Maximum command opens a dialog box where you can adjust the Intensity by moving the slider bar, clicking on the pointers at each end of the slider or entering a number from 1-16 in the textbox.
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