TECH TIPS
Power to the Pixel! Using Blending Modes in After
Effects
By Ben Bardens
Following
up on last issue’s Tech Tip, I will explore a simple and often
underused feature within After Effects called Blending Modes. Alone,
Blending Modes do not produce an animated result, and how to make
the best use of them may not be all that intuitive. But when combined
with other features, and applied to certain types of footage, Blending
Modes can achieve some really great effects and come up with some
really unique looks.
Blending Modes have a simple function; they control how the pixels
in the selected layer blend with the pixels in the underlying layer.
Blending Modes are not only found in After Effects, but also in Photoshop.
One way to think of Blending Modes is as a way of mixing the color
or tonal values of the pixels in your layers. The blended layer contains
the applied pixels, and the underlying layer contains the base pixels.
The combination of the two produces a new resulting pixel value.
Using Blending Modes couldn’t be easier. All you have to do
is display the Modes column within the Timeline and choose a Blending
Mode for a selected layer. As long as there is another layer underneath
that contains pixels of any value, you will most likely see an immediate
result.
To display the Modes column, do one of the following:
Click where it says Switches/Modes at the bottom of the Timeline
window to toggle between the switches panel and the Modes panel.
Click on the pop-up menu in the top right corner of the Timeline window
and choose Columns -> Modes to display the Modes panel without
replacing the Switches panel.
Once the Modes panel is visible, you can simply click on the pop-up
to specify a mode for any of your layers. There are several to choose
from. For a detailed description of each mode and the effect it produces,
choose Help -> After Effects Help and then click on Search and
type in Blending Modes. The modes in the pop-up menu are loosely arranged
into groups based on the type of result they produce. Some modes,
such as Lighten or Add for example, always result in lighter pixels.
Another group, including Multiply and Darken, always produce darker
pixels. And then there are other modes such as Overlay, which produce
varied results depending on the color and tonal values of the base
and applied pixels. The best way to get familiar with all the modes
is to experiment with them by cycling through them all until you find
one you like.
To cycle through modes do the following:
Select a layer and then push Shift + to cycle forward through the
Modes menu (push Shift _ to cycle backwards).
One question that often comes up in my class is, “Can I set
keyframes for Blend Modes?” The answer is no; however that isn’t
to say that Blend Modes can’t be animated. Blending Modes are
not properties, so they do not have their own keyframe values. Blending
Modes should be used along with properties that can be animated, such
as Opacity or Blurriness to produce an animated result.
In the following tutorial I will introduce some techniques for using Blending Modes to produce an animated result. Download the tutorial file from http://www.barkanimation.com/guild/19.zip.
Tutorial
Last issue, I introduced the 3-D Invigorator for After Effects (available
from www.zaxwerks.com),
a powerful third-party plug-in that enables you to create 3-D titles
and logos directly in After Effects. In this month’s tutorial,
I am going to start with the file called “3-D Logo.mov,”
which was created in the last tutorial. (This pre-rendered movie is
included in the tutorial download.)
Launch After Effects, create a New Project and import the 3-D Logo.mov
file.
Before adding any effects to the 3-D logo, we’ll create a background
for the movie.
Start by creating a New Composition. Name the composition Background
comp.
Specify a custom frame size of 1440x1080 using Square Pixels, and
29.97 fps and 4-second duration.
Import the noise.jpg file into your project.
Place the noise.jpg footage item into the Background Comp.
In the Background Comp, select the noise.jpg layer and choose Effect
-> Noise & Grain -> Fractal Noise.
Make sure your current time marker is at T=0 and in the Effect Controls
window,
Click the stopwatch for Evolution, leaving the value at 0.
Change the current time to T=3:29 and change the Evolution value to
2x0.0.
This will give our background an animated nebulous quality, like clouds
forming.
Close the Background Comp.
Create a new composition. Call it 3-D Logo Comp, specify a frame size
of 720x540 with square pixels, a frame rate of 29.97 and a duration
of 4:00.
Add the 3-D Logo.mov and Background Comp to the 3-D Logo comp by dragging
each to the timeline window so that they appear centered in the composition
frame.
Make sure the Background Comp layer’s in point is at T=0, and
place it at the bottom of the layer stack.
With the Background Comp layer selected, choose Effects -> Render
-> Cell Pattern.
In the Effect Controls window, specify the following settings:
Cell Pattern: Pillow
Invert: Checked
Contrast: 60
Disperse: 1.0
Size: 90
Click the stopwatch for Evolution, leaving the value at 0.
Change the current time to T=3:29 and change the Evolution value
to 1x0.0.
Save your project.
To apply the same camera view from our 3-D Logo.mov to our Background
Comp layer, we will need to add the camera from the last project.
If you have the project called 3-D Logo.aep from last issue, locate
it. Close the current project and open the 3-D Logo project. Select
the Camera 1 layer and choose Edit -> Copy.
Close the 3-D Logo project and re-open your new project. Place the
time marker at T=0 and choose Edit -> Paste.
If you do not have the project from last issue to perform the above step, create a new camera by choosing Layer -> New Camera. Choose the 50mm pre-set. Add the following keyframes for Position: T=1.0 P=730, -240, -670, T=2.06 P=360, 270, -1000, and at T=4.0 P=20, 270, -1000. Important: Make sure Point of Interest is not animated and has a constant value of 360, 270, 0. Uncheck the stopwatch if necessary. Lastly, select all three of the position keyframes and Cmd-click (Mac) or Ctrl-click (PC) on any one of them. This converts the keyframes into Auto-Bezier keyframes for a smooth steady motion.
Regardless of which of the above steps you took, continue by selecting the Background Comp layer and clicking its 3-D Layer switch (it looks like a little 3-D cube). The background will now take on the perspective controlled by our camera layer.
(Optional) To speed up previewing as you continue to add effects,
you may wish to pre-render the Background Comp layer. To do so, turn
off the Video switch for the 3-D Logo comp.mov layer. Choose Composition
-> Make Movie and specify Best Settings and Lossless with Alpha
from each of the pop-up menus in the Render Queue window. Click on
Lossless with Alpha and specify a Post Render Action of Import. Click
on Output To and name the file Background Comp.mov. Click Render.
When the render is complete, place the new Background Comp.mov from
the Project window into the Timeline, placing it above the Background
Comp layer. Make sure its in point is lined up at T=0. Disable the
Video Switch for the original Background Comp layer, turn the Video
switch back on for the 3-D Logo comp.mov layer and then continue on
with the following steps.
Build a RAM preview by pushing the Zero key on your numeric keypad.
At this point, we’ve got an interesting animation, although
the colors are lifeless and dull. This is where using Blending Modes
and a few simple filters will take our project to the next level.
You can experiment with the settings below to produce a result you
like. In the sample file I did the following:
Duplicate the 3-D logo layer. Select the bottom copy and apply the
Gaussian Blur filter to the layer. Specify Vertical for Blur Dimensions.
Set the current time to T=1:18 and click the stopwatch for Blurriness.
Move the current time to T=3:00 and change the Blurriness to 250.
Change the layers Blend Mode to Linear Light.
As an organizational technique, click on the layer’s color label
to the left of the layer name and change it to a different color.
Duplicate the layer six times.
Repeat the first five steps, except this time specify Horizontal for
Blur Dimension and only duplicate the layer twice.
I then made two more duplicates of the original 3-D Logo.mov layer
and placed them above the original. One with Overlay mode and the
uppermost with Luminescent Premultiply mode. For the Overlay layer,
I then animated Opacity, creating a fade from 0% to 100% from T=1.0
to T=2.06. For the Luminescent Premultiply layer, I animated Opacity,
creating a fade-in from T=3.11 to 3.20.
For the Overlay layer, add Effect -> Adjust -> Threshold. Specify
a Threshold Level of 158.
Lastly, I duplicated the Background comp.mov layer and added the
Effects -> Image Control -> Tint filter. Use the Map Black To
eyedropper to sample a beige color from the comp window and slide
the Amount to Tint value to about 30%. Place the layer in Overlay
mode and duplicate it one more time.
At this point, with all these layers and modes, your computer has
probably slowed to a crawl. You can reduce your preview quality by
clicking the pop-up in the Comp window and changing it from Full to
Half or less. Using Blend Modes and blur filters requires a lot of
computing power because of all the pixel blending occurring on each
frame.
To finish off the project create a new composition called Transition
comp, again using the 720x540 pre-set with a 4-second duration. Place
the 3-D Logo comp into the Transition comp. With the layer, selected
choose Effect -> Transition -> Linear Wipe. Set the following
keyframes for the Linear Wipe filter:
At T=0, set Transition Completion to 100% and click the stopwatch.
Change Wipe Angle to 16 degrees and click the stopwatch.
Select the Wipe Angle keyframe and choose Animation -> Toggle Hold
Keyframe to prevent the Wipe Angle from in-betweening.
At T=1.15, change Transition Completion to 0%.
At T=3.24, add another Transition Completion keyframe leaving the
value at 0%. Change Wipe Angle to 90 degrees.
At T=3.29 change Transition Completion to 100%.
Render your movie from the Transition comp using the Best Settings
and Lossless with Alpha presets. The resulting movie will be suitable
to use as a custom logo wipe that can be dropped on top of a cut point
in your editing environment.
Hopefully this tutorial helps to give you ideas for using Blend Modes along with other filters and properties to create some interesting visual styles. While it’s easy to make a mess with Blend Modes, keep experimenting and you’ll start to discover unique visual styles that you really like.
Guild member Ben Bardens runs a graphics studio and works as an editor/technical director in the Burbank area. He teaches After Effects and Photoshop at Glendale Community College and can be reached at bbardens@glendale.edu. Find out more about his classes at www.glendale.edu/~bbardens.
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