It’s easy to scrutinize the quality of a video clip, but the eyeball test is deceptive and will fail even the most seasoned editor. The human visual system has the uncanny ability to correct flawed images, shifting color’s perception deep within the cerebral cortex. Pair that ability with variances in display technology and you have the recipe for an image disaster. For this reason, the toolset contained within a preview monitor is critical for post-production success.
Every major video editing application equips the preview monitor window with a suite of tools to evaluate, measure, and deliver an accurate display of the video image. Understanding these tools and how to use them will help you to craft an image that is consistent and true– just the way you want your audience to see it.
Safe Zone Guides
A simple but powerful tool on the preview monitor are the overlay guides, most notably the Action Safe and Title Safe area guides. When the safe zone guides are activated, the preview monitor displays two concentric rectangles that overlay the video image towards the outer edge of the screen. The safe zone guides provide a practical forecast of what will be safely framed for the audience. They also serve as a simple design tool for the alignment, layout and display of graphics.
The safe zone guides provide a practical forecast of what will be safely framed for the audience.
The inner rectangle is the Title Safe guide. It establishes an area for any titles or graphics that you intend to place in the video. Anything that falls within this area is safe to be read by the audience and will not be cropped out by the edge of the final display device.
The outermost guide is the Action Safe guide; anything that happens within this area is generally safe to make it to screen for the viewer. The other purpose of the Action Safe guide is to establish a perimeter within the video. If graphics are placed within the Title Safe region, the Action Safe region is the portion of the video that will be a buffer, or a margin for the graphics and the edge of the screen.
The various scopes found in video editing applications are used to calibrate and align the color qualities and brightness values of a video image. These powerful tools provide an accurate measure of the technical chromatic and luminance values within the image. When used correctly, they give you an unbiased analysis of these values and allow you to make adjustments to these values so the video output will have accurate colors.
The Waveform Monitor deals with the luminance properties of the image. It reveals the grayscale values across the screen with the brightest values being indicated at the top of the monitor, ranging down to the darkest values at the bottom of the screen. There are normally horizontal lines evenly distributed across the waveform monitor. These lines indicate specific values and section off the different ranges of gray-scale values. It’s considered best practice to keep all values between the pure white 100 line, second from the top, and the true black zero line, second from the bottom. This will help to keep the image from blowing out or falling off too drastically.
Similar to the waveform monitor is the RGB parade, which functions in much the same way as the waveform monitor. Instead of solely measuring the luminance values of the entire image, it measures the luminance values of the separate RGB channels. It’s a helpful tool when trying to balance the overall color of an image.
The vectorscope measures the overall chrominance, or color values of the image. It’s arranged in a radial format with specific color targets marked on the scope. The angle at which data reads on the scope is indicative of the color being displayed, while the proximity of the data in relation to the center of the scope indicates saturation. The further a point is from the center, the higher its saturation value. The use of a color target card on set and a vectorscope in the edit bay can make color correction a simple process.
A monitor that is properly calibrated will save you valuable time. Display devices come in all shapes and sizes, since image quality can be adjusted, it’s a common occurrence that an image will appear subtly different for each screen it’s displayed on. You can’t control every screen your work goes to, but you can control your own screen. The use of a screen calibration device and of software will help you to set up your monitor so its colors are accurate and match the true value of the image as represented in the scopes.
As video editors, we look at a lot of things–most notably our output monitor. It’s easy to look at the preview monitor as just another window, but it’s more than a pane in the NLE, it’s a toolkit that offers an honest view of what you have on screen.
Chris “Ace” Gates is a four time Emmy Award-winning writer and producer.