Primatte Keyer Pro 4 for Adobe After Effects: Getting Started

Primatte Keyer 4 from Red Giant Software has a host of professional options for creating mattes from any object shot against a color background. In this section we will cover the Primatte Keyer for After Effects interface, explaining the function of each button and menu item.

While Primatte Keyer is a chroma keyer, and thus can create a matte from any color background, for the purposes of this documentation the element to be keyed will be referred to as the “bluescreen” element.

Applying Primatte

Primatte Keyer is accessed like all filters from within After Effects. Make sure that your foreground element is highlighted in the timeline. Primatte Keyer is accessed by selecting Primatte Keyer 4.0 from the Primatte sub-menu, located under the Effect menu.

Primatte is applied to the foreground layer, and the interface appears in the Effect Controls palette.

Interface

The Primatte Keyer interface is contained in a single tab in the Effect Controls palette.

All Primatte keying functions can be accessed through this interface. There are four main components to the Primatte interface:

• Deartifacting

• Keying

• Alpha Controls

• Composite Controls

The Effect Controls Interface

Most of the tools in Primatte Keyer require you to sample areas of the foreground element and the color key area in the After Effects Composition window using the arrow tool. Usually, when you click and drag on a clip with the arrow tool you reposition the clip. To prevent the clip from moving the Primatte Keyer effect must be highlighted in the Effect Controls window.

When the Primatte Keyer effect and arrow tool are selected, the arrow tool is changed by Primatte to work as an area sampling tool. When the Primatte Keyer effect is deselected, the arrow tool functions as expected and other tools may be accessed from the tool palette.

The effects name in After Effects unselected on the left, and properly selected for keying operations on the right When using Primatte Keyer, if you try to sample an area of your foreground element and it moves as you drag the mouse, make sure that the words Primatte Keyer are highlighted in the Effect Controls window. When these words are not selected as in the left hand image above, sampling in Primatte is disabled. When the words are selected as in the right hand image above, sampling is enabled.

If your image shifts when you go to sample (as in the above example), your Primatte Keyer effect has become deselected in the Effect Controls palette.

In the example above we see a correct sample. The Primatte Keyer effect has been selected in the Effect Controls palette.

When switching between the Effect Controls window and the Composition window while using the Primatte Keyer tools, click on the title bar at the top of the Composition window to bring it to the foreground, and the Primatte Keyer name when switching back to the Effect Controls window. By using this technique you will not have to reselect the Primatte Keyer effect to continue working.

Sampling Pixels

At this point it is important to provide a brief overview of how to sample pixels, because understanding the sampling process directly relates to Primatte features that will be explained and described in subsequent sections below.

What is sampling? The Primatte keying process requires you to designate areas of your bluescreen element as either foreground (fully opaque) or background (fully transparent). Primatte Keyer will then generate a matte (also commonly referred to as an alpha channel) based upon these selections. This process is known as

Sampling

Sampling involves selecting an area of the composite with the mouse pointer. You can either click once to select a single pixel, or click and drag the mouse to select multiple pixels in a single operation.

There are three ways to sample pixels, using either a Point, Rectangle or Median sampling.

Point Sampling

Those of you who are familiar with previous Primatte releases for After Effects will be familiar with point sampling.

With the arrow tool selected, simply click once to sample a single point, or click and drag to sample multiple points. As you drag, small dots will appear along the path of the mouse movement. Each one of these small dots represents a sampled pixel. Once you release the mouse button Primatte will generate a key based on the sampled pixels.

Only pixels directly under one of the dots in the trail are sampled. When trying to select a specific pixel with the point sample, move the mouse more slowly to create a denser sample area.

Rectangle Sampling

In Primatte Keyer we added in an often-requested feature, the ability to sample pixels using a rectangle. This works in exactly the same manner as the point sample, only you are sampling all of the pixels within a rectangular area rather than underneath the dot trail.

Click and drag in the composite window to select a rectangular range of pixels. When you release the mouse button Primatte will generate a key based upon the sampled pixels.

Median Sampling

The Median Sampling Option is the same as Point selection except that each point is the result of taking a 3x3 region around the point the user clicked and then applying a median filter. This can potentially reduce any noisy pixels.