Walker Effects Manual
- Installation
- Alpha Tool
- Channel Composite
- Channel Lighting
- Channel Noise
- Channel Offset
- Channel Range
- Channel Viewer
- Color Composite
- Color Fill
- Colorize
- Color Space
- Composite
- Crazy Stripes
- Glow
- Gradient Designer
- Light Wrap
- Stargate
- Super Histogram
Channel Range
This plug-in is a powerful tool for generating and manipulating mattes and transitions by easily allowing you to isolate specific grayscale ranges of channels. The range can be quickly animated with full control over falloff, repeating, and cycling.
There are several basic components to the Range Controls interface:
The Histogram area can be dragged to interact with the Cycle control. The cursor will change to a hand as an indication.
The following controls are only available when the View Mode is set to Composite. With the Composite option, the resulting channel range can be directly combined with the source layer. The source layer is always the layer on which the effect is applied. These options are kept intentionally simple. For more control, it is suggested that you use Channel Composite or Color Composite.
View Mode
To help facilitate the setup of Channel Range, there are several View Modes. Each mode affects what controls are available and also streamlines rendering for that particular mode.Input Layer
This option will display the Input Layer to the effect, specified by the Input Layer popup menu. If the layer is set to None then Channel Range will use the layer on which it is applied. With this View Mode, no rendering takes place and the Input Layer is simply passed through the effect.Input Channel
After choosing an Input Layer, use this mode to view the Input Channel, specified by the Channel popup menu. The Invert and Premultiply With Alpha checkboxes apply to this channel.Range
The Range View Mode will render out the selected channel range in grayscale. It is best to use this mode when you do not need to recombine the range with the input layer. The range is primarily controlled by the In, Out, Fade In, Fade Out, and Cycle controls.Composite
For maximum flexibility Channel Range provides the Composite View Mode to allow you to composite the range over the source layer. Not to be confused with the Input Layer, the source layer is the layer on which the effect is applied. This makes it possible to apply Channel Range directly into the alpha channel, or use the range to modify the source in another way.Input Layer
This specifies the layer that Channel Range derives the range from. If None is selected, then the layer on which the effect is applied will be used.Channel
You can choose from a long list of channels to base the range on. This channel is extracted from the Input Layer and affected by the Invert and Premultiply With Alpha checkboxes.Invert
When this is enabled, the selected Channel will be inverted. This is processed before Premultiply With Alpha.Premultiply With Alpha
Use this option to incorporate the Input Layer's alpha channel with the selected channel. Otherwise the full unaltered channel value will be used.Range Controls
The custom interface makes defining and working with ranges easy. It is directly linked to the slider controls. Any of these controls can be animated by enabling keyframing for them.There are several basic components to the Range Controls interface:
Control Bar
The Control Bar is at the top of the interface. The gray text in the upper left corner of the interface tells you the names of each control. As the mouse moves over each element, the name will update to reflect the name of the control. This is helpful to know what you are selecting before clicking on it.Display Histogram Gradient
The first button on the Control Bar toggles between displaying the histogram in black or as a gradient.Reset Cycle
The middle button on the Control Bar will reset the Cycle value to 0, centering the curve in the range view. The remaining range controls are unaffected.Reset to Default Positions
The button on the furthest right resets all of the range controls to default.Histogram
For visual reference, the Histogram shows the distribution of grayscale values within the Input Channel. Each vertical spike in the Histogram directly correlates to the grayscale value below it in the Input Gradient and represents the number of pixels counted with the same value. The Histogram allows you to see where channel data starts and ends, and in what areas the channel is the densest. This can make it much easier to create transitions and to exclude or include certain grayscale levels of the image.The Histogram area can be dragged to interact with the Cycle control. The cursor will change to a hand as an indication.
Histogram Scale
The slider control on the right side of the interface controls the vertical display scale of the histogram. Use this to zoom in to see smaller histogram details.Range Curve
Plotted in red over the histogram is the the Range Curve. This depicts what range of the channel is being selected. The curve directly correlates to the Output Gradient. The Range Curve can be modified in the interface or by using the independent sliders.In
Represented as a green line, the In control specifies at what point the Range Curve becomes 100%. The Range Curve ramps in from Fade In. The In point can never be greater than Out.Out
Represented as a red line, this is the beginning of the end of the Range Curve. From In to Out the range is at 100% value, but from Out to Fade Out, the Range Curve ramps down. Out cannot be less than In.Fade In
Represented as a blue line, Fade In specifies the starting point of the curve. By default, Uniform Fade (in Advanced Options) is enabled, causing Fade In to also set the Fade Out parameter. Fade In is measured as a relative distance from the In point. To change the curvature of the Range Curve see the Advanced Options Curve Type.Fade Out
By default the Fade Out control is mirrored to Fade In and is also represented as a blue line. Changing Fade Out will affect Fade In. However, you can turn off Uniform Fade in the Advanced Settings to get an independent Fade Out control, represented as a purple line. Fade Out is measured as a relative distance from the Out point.Input Gradient
The gradient just below the histogram represents the input grayscale values. This gradient never changes, always ranging from black to white, as a visual guide for both the Range Curve and Histogram.Output Gradient
The Output Gradient is a grayscale representation of the Range Curve. By default, Normalize Output Gradient (under Advanced Options) is enabled and forces the Output Gradient to always range from full black to full white. If this option is turned off, then the Output Gradient will be based on the input values of the channel.In
The In slider sets the point at which the Range Curve becomes 100%. This value cannot be greater than the Out point.Out
This sets the point at which Range Curve begins to ramp out. Between the In point and Out point, the Range Curve is at 100%.Fade In (& Out)
Measured from the In point, Fade In specifies the distance to begin fading the Range Curve in. The curve from Fade In is controlled by the Curve Type in Advanced Options. When Uniform Fade is enabled, this slider is renamed Fade In & Out and controls the Fade Out amount as well.Fade Out
By default the independent Fade Out control is disabled and is controlled by the Fade In & Out slider. If Uniform Fade in Advanced Options is disabled, then the Fade Out can be specified independently. Fade Out is measured as a distance from the Out point.Cycle
The Cycle feature offsets the entire Range Curve without modifying the actual values of the In or Out points. The Cycle control offers an easy way to move the Range Curve through the channel and create transitions and other effects. One full rotation of the Cycle moves the Range Curve through one complete gradient. Cycle can also be modified in the Range Controls custom interface by dragging in any empty area inside the curve viewing box (the cursor changes to a hand as an indicator).Advanced Options
The following set of controls provide further options for customizing and controlling the Range Curve.Normalize Output Gradient
When this checkbox is enabled, the resulting Output Gradient will always be normalized to a full spectrum of black and white values. Otherwise, if the checkbox is unchecked, the Output Gradient will be based on the existing grayscale values in the Input Channel.Uniform Fade
When this is enabled, the Fade In and Fade Out values will be merged into a single Fade In & Out control. In the Range Controls interface, changing one value will affect the other.Curve Type
There are two types of curves available with Channel Range: Natural and Linear. The Natural curve type is the default and will produce a smooth curve based on Gaussian distribution. The other option, Linear, causes the Range Curve to interpolate in straight lines. The Curve Type can be set independently for the Fade In and Fade Out if Uniform Fade is unchecked, otherwise the Curve Type will affect both sides of the range.Bias
The Bias can be used to further bend the Range Curve, swaying it one way or the other. Bias works for both Natural and Linear curve types. The default value of Bias is 1.0 and has no effect on the curve. Setting a value less than 1.0 will make the curve more concave and pull it closer to the center point of the range. A value greater than 1.0 will cause the curve to be convex and move further from the center of the range.Repeat
The Range Curve is not limited to just a single peak. You can create infinite repetitions of the Range Curve Left, Right, or Left & Right of the initial curve. Repeating the range is very useful in combination with the Cycle control. Cycle can be animated to create repeating 'waves' that move through the channel. When Repeat is disabled, the Range Curve has no value before Fade In or after Fade Out.Repeat Spacing
When Repeat is enabled for any direction, this slider becomes available to set the distance between repetitions. The value is measured in the same units as the Cycle parameter. One full rotation of the Cycle is equal to a Repeat Spacing of 1.0. So for example, if you set Repeat Spacing to 1.0, as the Cycle passes 1 full revolution the first curve is just leaving the frame while the next curve is just entering. The Range Control interface measures from 0 to 1.0 from left to right. Repeat Spacing can only be a positive number since curves cannot overlap.Invert Range
After creating a range, you may discover that you need the inverse value. You can do this by simply turning on Invert Range. This is not to be confused with the previous Invert control, which affects the Input Channel only.The following controls are only available when the View Mode is set to Composite. With the Composite option, the resulting channel range can be directly combined with the source layer. The source layer is always the layer on which the effect is applied. These options are kept intentionally simple. For more control, it is suggested that you use Channel Composite or Color Composite.
Destination Channel
You may use the Destination Channel popup to specify a channel to composite the effect result to. The default choice RGB will composite the channel range to the color channels of the source layer. A common choice for this feature is to specify Alpha so that Channel Range works on the transparency of the layer.Composite Mode
How the channel range is mixed with the Destination Channel is set by the Composite Mode. The default Composite Mode is Normal, to replace the existing channel values with that of the channel range. Using other Composite Modes can be beneficial when adding or subtracting from a matte layer, or creating special effects within the color channels.Opacity
The Opacity affects how much the channel range affects the Destination Channel. If Opacity is set to 0, Channel Range has no affect on the layer.
