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
Super Histogram
Super Histogram is a useful tool for inspecting image data and viewing color distribution. This can help you determine whether an image has 16 bit data, if gradients are smooth or what the high and low ranges of each channel are. It can be used in conjunction with other color correction tools to more clearly see how adjustments are affecting the color range.
Note: When you have Render Output turned off it may be a good idea to use the caps lock key or turn the plug-in off to get better feedback while using the histogram controls.
Note: The colors of the histogram are meant to conveniently show information and do not represent the actual colors of the image.
When the Sample mode is set to Region, you will have the ability to specify the Position, Width and Height of the region. The region is measured in pixels located around the center Position.
Above is a histogram comparison between an image that was originally 8 bit converted to 16 bit (left) and an original 16 bit image (right). You can easily see that the 8 bit image is banded and does not have a smooth spectrum.
Super Histogram provides a method of visualizing and diagnosing issues with color space and channel data. However it is really beyond the scope of this plugin to fix problems that may be encountered. For example, if you have an image that is supposed to be 16 bit but you discover that somewhere along the line it was converted down to 8 bit, there is no post-process that can be applied to retrieve the lost information.
In the end, Super Histogram is a tool that will help you make better production decisions and set up your projects more effeciently. When you are working on a film project where 16 bit color is critical, this plugin can be a very handy tool for checking your work and preventing wasted time and money by filming out incorrectly rendered sequences.
Color Model
Super Histogram allows you to view the channel data of all major color models, including RGB, HLS, CMYK and many others. Each color model provides its own unique view into the image, giving you more insight and information to make decisions on using particular filters or color corrections.Render Output
When this checkbox is turned on, Super Histogram will render the image through the Color Model filter and render the highlighted selection into the image. Selections are made using the Selection Tool and the color is set using the Selection Color button.Note: When you have Render Output turned off it may be a good idea to use the caps lock key or turn the plug-in off to get better feedback while using the histogram controls.
Histogram
The main histogram is a custom user interface with the ability to zoom, pan and select individual or ranges of data columns.Histogram View
The histogram graph represents a count of pixels for each grayscale value of each component channel. It can be thought of as a huge bar graph, where the columns from left to right represents the channel values and the data up and down represents the number of pixels counted for each value. Channel values are measured as a shade of gray, where the scale depends on the color depth your project is set to. For a regular 8 bit image there are 256 levels of gray, so the histogram would measure from 0 to 255 from left to right. And for a 16 bit image it would measure from 0 to 32768.Control Bar
The Control Bar above the histogram displays useful information about the current tool or describes a control when the mouse moves over it. When using the Selection Tool the Control Bar will display the min and max values of the currently selected range and the total number of selected pixels. If a single column is selected, the index value of the selection will be displayed along with the number of contributing pixels. When the Selection Tool is off, the Control Bar will display the lowest and highest values of the entire histogram and the total number of pixels counted in the image or defined region.Channel Toggle Switches
These switches enable you to view image channels in isolation or in custom combinations. The names of each switch change based on the Color Model selected. When viewing more than one channel at the same time, the histogram always favors the largest channel value. You may view a single channel in solo mode by holding the control key while clicking on the channel toggle switch.Selection Tool
The Selection Tool provides a way of interacting with the histogram data. You can click on the histogram to select individual data columns, or you can click and drag to select a range of data. When data is selected, information regarding the selection is shown in the Control Bar. Also, if you have Render Output enabled you can see the selected pixels in the image. Clicking on the Selection Tool button turns the selection view on and off. With the Selection Tool off, the selection will no longer be visible in the histogram or the rendered image.Selection Color
Clicking this control will open the system color picker allowing you to select the color in which selected data and pixels are displayed. The selection color affects the histogram as well as the rendered image if the Render Output option is turned on. The Selection Color button is only available when the Selection Tool is turned on.Color Display
This toggle switch gives you the option to view the histogram in full color or as solid black following the tradition of Photoshop and the standard Levels filter. When displaying the histogram in color, the alpha channel is colored inversely to the background color of the display and is shown superimposed over the color channels as a series of black dots or lines. The display colors are designed to maximize visibility of all channels.Note: The colors of the histogram are meant to conveniently show information and do not represent the actual colors of the image.
Reset
This button will reset the histogram view in a number of ways:Single Click
A single click automatically scales the view both horizontally and vertically to fit all the information in the view. This is useful for immediately viewing the histogram for any image and getting the lowest and highest value in the channel.Double Click
This also resets the histogram view, however it zooms out completely on the horizontal axis. This will set the black point to 0 and and the white point to the highest value depending on color depth (255 or 32768).Triple Click
The last option of the reset button is invoked by clicking 3 times quickly. This will reset the histogram view as well as set all the controls back to their default settings including the Selection Color and the state of all the toggle switches.Black and White Sliders
The black and white sliders allow you to interact with the histogram view by zooming the data horizontally. There are also two modified modes for interacting with these sliders:Option/Alt Key
Holding down the option/alt key while dragging the slider will uniformly zoom the view in or out. Dragging the mouse to the right will zoom the view out while a mouse movement to the left will zoom the view in.Control Key
Holding the control key while dragging the slider will pan the view left or right. This preserves the distance between the black and white slider while moving them in unison.Scale Slider
The slider control on the far right of the histogram display controls the vertical scale of the histogram. This is useful when you are trying to look at smaller data that may not be visible in a normal view. When you click on the Reset button, the scale will automatically be set to fit the view containing all visible data of the histogram.Sample
The Sample mode lets you choose between using the Whole Image or just a Region to build the histogram. Normally histograms deal with the whole image, but Super Histogram provides a Region view to give you maximum flexibility to inspect image data.When the Sample mode is set to Region, you will have the ability to specify the Position, Width and Height of the region. The region is measured in pixels located around the center Position.
Tips
Rendering
Super Histogram is really designed as an informative plug-in and not a rendering plug-in. That means that you can use Super Histogram to analyze an image or layer, but you should not rely on it for rendering channels or selections and it is best that you turn off the filter after you are done using it. To learn more about working with color spaces and image channels please see the Color Space and Channel Viewer plug-ins.Performance and Caps Lock
Whenever you interact with the custom user interface of Super Histogram, After Effects will attempt to rerender the image because it believes some change is occurring. In most cases you can get better feedback by either turning the plug-in off or turning on caps lock. Once Super Histogram has read the frame it does not need to read it again unless a change has occurred. The exception is when you have enabled the Render Output option and are expecting to see render results from Super Histogram.Alpha Channel
By default the Alpha channel toggle switch is off. This is by design because quite often the alpha channel contains a large amount of pure white pixels. This will throw off the automatic scaling of the histogram view and in many cases it may appear that there is no data in the image because the view is zoomed out so far.8 bit vs 16 bit
Super Histogram automatically adjusts its bit depth to match the project. So in order to switch between 8 and 16 bit, you must use the switch in the After Effects Project Window (option-clicking the button will change it) or select from the application menu: File>Project Settings.Determining 16 bit Data
Having an After Effects project set to 16 bit does not automatically ensure that any given image will be 16 bit. However using Super Histogram you can easily look at the image data to determine whether the pixel data is 16 bit or not. The telltale sign is when there are big gaps between columns of data. An 8 bit image converted to 16 bit will not have pixel values across the whole range and therefore will produce columns of data at certain integral points. Conversely when you are looking at a true 16 bit image, there will be a continuous flow of data from left to right without spaces. Also, the data will appear much smaller because there are fewer pixels in comparison to the range of the channel data.8 bit Data
16 bit Data
Above is a histogram comparison between an image that was originally 8 bit converted to 16 bit (left) and an original 16 bit image (right). You can easily see that the 8 bit image is banded and does not have a smooth spectrum.
Correcting Problems
Super Histogram provides a method of visualizing and diagnosing issues with color space and channel data. However it is really beyond the scope of this plugin to fix problems that may be encountered. For example, if you have an image that is supposed to be 16 bit but you discover that somewhere along the line it was converted down to 8 bit, there is no post-process that can be applied to retrieve the lost information.
In the end, Super Histogram is a tool that will help you make better production decisions and set up your projects more effeciently. When you are working on a film project where 16 bit color is critical, this plugin can be a very handy tool for checking your work and preventing wasted time and money by filming out incorrectly rendered sequences.
