While we have been exploring color using three channels until now, there's actually an important fourth: alpha. The alpha channel for each pixel defines the opacity of the pixel. The lower the opacity, the more of the background behind a pixel will be revealed. The alpha channel works in exactly the same way as the color channels, but the results when changing it can be surprising, because the outcome is a combination of foreground and background pixels. Learn more in this video.
- [Instructor] So far, we've just been looking…at color and light,…and one way or another, we've been using three channels…of color information for each pixel.…Let's use RGB for now.…There's another piece of information that's important…about pixels, and that's how transparent they are.…The words used to describe how opaque a pixel is vary.…Sometimes, it will be opacity, transparency or alpha.…Regardless of the name, when you make an adjustment to…the opacity of a pixel, you're actually adjusting…a separate channel, the alpha channel.…
Adjustments made to the alpha channel are…completely separate from adjustments…made to the color channels.…If you reduce the alpha channel level,…the colors will stay the same,…but some of whatever is behind the pixel will show through.…Because most video editing timelines are black…in the background, reducing the alpha channel,…which is often described in software as…lowering the opacity, will appear to make the image darker.…And this isn't really true.…In fact, you're seeing a combination of the color…
Get ready to remove the mystery behind terms you've encountered. If you work in a creative profession, this can enhance your command of the tools you use. Learn what a pixel really is, what color channels are, and what audio frequency is. Discover how color channels, bit depth, and video frame rates work. Find out the difference between codecs and file formats, and how compression is involved. By the end of this course, you'll know how to answer common client questions—like, whether a logo should be supplied in vector or bitmap form, and more.
Note: Motion graphics in this course were provided by Chelsea Parrish: chelseaparrish.com.
- What is a pixel?
- Aspect ratios
- Bit depth
- Alpha and transparency
- Light and color channels
- Color modes: RGB, YUV, CMYK
- Camera depth of field
- Chroma Key and Luma Key
- Blend modes
- Color wheels, vectorscopes, and waveforms
- Video compression and codecs
- Frame rates and timecode
- File formats
- Audio amplitude
- Capturing audio tone as frequency
- Audio timing using the phase
Skill Level Beginner
Learning Video Production and Editingwith Rob Garrott19m 25s Beginner
Video Foundations: Cameras and Shootingwith Anthony Q. Artis2h 58m Appropriate for all
Introduction to Video Dialogue Editingwith Ashley Kennedy3h 14m Appropriate for all
1. How Do Computers Think?
2. How Cameras and Computers Think about Color
3. The Language of Color
4. The Shape of Your Picture and the Speed of Your Video
5. Storing Everything (Codecs)
6. Color Wheels, Vectorscopes, and Waveforms
Understanding waveforms2m 39s
7. Making Changes
8. Audio Made Simple
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