Pena Contents
Introduction
Control Pane
Brush Pane
Texture Pane
Effects Pane
Color Picker
Save/Load Pane
Selection Pane
Preferences Pane
Intelligent Canvas
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Jot Bluetooth Stylus
 
The Effects Library
Effects Introduction
Color Source Effects
Procedural Source Effects
Color Filter Effects
  • Color Filter Introduction
  • Average
  • Blend
  • Brightness
  • Contrast
  • Desaturate
  • Exchange Channels
  • Invert
  • Maximum
  • Minimum
  • Saturation
  • Swap
  • Tint (Modify HSB)
  • Transparency (Alpha)
  • Spatial Filter Effects
    Math and Logic Effects
    Special Effects
     
    Artists Gallery
    The Artist Gallery
     
    Pena Support
    Troubleshooting

       

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      Effect:Contrast
      Category:Color Filter
      Speed:Fast

      Description: The Contrast Effect lets you adjust the Contrast and Brightness of either Color 1 and/or Color 2. Contrast is the overall dynamic range of a color.

      The math is expressed as follows (just for interest):

      Result = (ColorN*Contrast)+Brightness

       
      Options: The Contrast Effect has the following Options Pane:

      Contrast:This value sets the amount to increase or decrease the contrast. The value 1.0 will have no effect. Values higher than 1.0 will heighten the contrast. Values lower than 1.0 will lessen the contrast.
      Brightness:This value sets the amount to increase or decrease the brightness. The value zero will have no effect. Values higher than zero will brighten the selected color. Values lower than zero will darken the selected color. Brightness is often used in conjunction with Contrast. When Contrast is increased, the overall brightness of the color also increases, meaning you might want to decrease the Brightness value to compensate. Likewise, decreasing the Contrast will decrease the overall brightness, meaning you might want to increase the Brightness value to compensate.
      Affect Color 1:If set to a Green Check Mark the Color 1 will be modified by the Contrast and Brightness values. When set to a Red X Color 1 is not changed.
      Affect Color 2:If set to a Green Check Mark the Color 2 will be modified by the Contrast and Brightness values. When set to a Red X Color 2 is not changed.
      Modify Red:If set to a Green Check Mark the Red Channel will be modified by the Contrast and Brightness values. When set to a Red X the Red Channel is not changed.
      Modify Green:If set to a Green Check Mark the Green Channel will be modified by the Contrast and Brightness values. When set to a Red X the Green Channel is not changed.
      Modify Blue:If set to a Green Check Mark the Blue Channel will be modified by the Contrast and Brightness values. When set to a Red X the Blue Channel is not changed.
      Modify Alpha:If set to a Green Check Mark the Alpha Channel will be modified by the Contrast and Brightness values. When set to a Red X the Alpha Channel is not changed.

      Example: To show the Contrast Effect we will take our Arches National Park image and load it into Slot 1 using the Texture Effect. In Slot 2 we have our Contrast Effect.

      The following three images show:

      1. The normal image with no changes. Contrast is set to 1.0 and Brightness is set to 0.0.
      2. A Contrast value of 1.25 and Brightness value of 0.0. This increases the contrast (dynamic range) of the image.
      3. A Contrast value of 0.5 and Brightness value of 0.0. This decreases the contrast (dynamic range) of the image.

       

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