How to read a Vector Scope and Waveform Monitor
Understanding how to read a waveform monitor and a vector scope is the first step in being able to effectively shade cameras on a live production. Waveform monitors and vector scopes are essential tools for video professionals to ensure that their content meets technical standards and looks visually appealing. These instruments are used to analyze and measure the different characteristics of a video signal, including brightness, contrast, color, and hue. These tools are important for the shader to be able to match the look of multiple cameras quickly and accurately.
Understanding the Video Waveform Monitor
A video waveform monitor displays the luminance levels of a video signal, from black to white, as a graph. The vertical axis shows a range from 0 IRE at the bottom, representing the blackest part of the image, to 100 IRE at the top, representing the brightest part. This is important to note, as most monitors cannot display brightness values outside of this 0-100 IRE scale. If the black level is too low, the image will appear dark and lacking in detail. If the black level is too high, the image will appear washed out and lacking in contrast. The same applies to the white level, only in the reverse. Anything over 100 IRE is too bright and will be lacking in detail, while whites under 100 IRE will seem dull and washed out.
An important note is that grass (green) typically is at 40-50 IRE, and Caucasian skin tones are typically between 65-75 IRE.
The video waveform monitor can also display the level of the color channels in a video signal, specifically red, green, and blue. This can be useful in identifying color balance issues in an image. The color channels are displayed as separate patterns on the waveform monitor, and they should be roughly the same level in a typical situation.
Understanding the Vector Scope
A vector scope is a circular graph that displays the color and saturation information of a video signal. The horizontal axis represents the color along the blue-yellow (B-Y) axis, while the 2 diagonal axes represents the color along the red-cyan (R-CY) axis and green-magenta (G-MG) axis respectively. The center of the vector scope represents neutral colors (white and black), while the outer edge represents the most saturated colors (100% saturation).
The color channels of the image are displayed as “vectors” on the vector scope, with the length of the vector representing the saturation of the color and the angle of the vector representing the hue. When shading a camera, typically you are either adding or subtracting red, blue, and green from the image, shifting the vectors closer or farther from the targets on the vector scope.
A good way to confirm your camera gets a good white balance is by looking at the center point of the vector scope while the camera is shooting a white object. If the camera is properly white balanced, the dot on the scope should line up with the center cross on the vector scope.
Conclusion
A video waveform monitor and a vector scope are essential tools for video professionals to ensure that their content meets technical standards and looks visually appealing. By understanding how to read these instruments, you can identify and correct technical issues in your video content, as well as achieve creative effects. With practice and experience, you can use a video waveform monitor and a vector scope to improve the quality and impact of your video content.