Below is a photo of our Production Assistant in our video production studio holding the two printing test charts which show a resolution beyond 4k.
The EBU (www.ebu.ch) and the RAI (www.rai.it) and a further few industry partners have organized a test sequence shooting for 4K@50 and 3D stereoscopic at 1080p/50 per eye. This is being done in Turin between june 11th till the 22nd. And we at NoStairway Media cannot wait to see the results!
But why are video production test charts important?
Professional video production must be as close to perfection as possible to profit from your work. As let’s face it, no one is going to buy something with constantly changing focus, light levels or colours. This is why test charts and other calibrating gadgets are so important in this industry.
Test patterns are used to illustrate weaknesses in displays and help users to adjust their screen to achieve the best possible image. CRT displays exhibit more weaknesses than flat-panel displays do, especially in the corners, and that’s why test patterns often show the same image in each corner. Test charts also illustrate weaknesses in video cameras, examining the correct colour resolution of the equipment and to calibrate scenes to capture an identical representation between multi-camera shots.
Additionally these test charts can help the camera obtain proper focus, aperture, white balance and reveal any weaknesses in the camera lens. If the camera has any trouble capturing portions of the resolution chart, then it’s more than likely to have trouble capturing fine lines and other details. For instance, if you shoot a gray scale chart and all of the gradations from one shade to another don’t show up in the captured footage, then dark scenes shot with that camera will probably lack contrast and detail. Colour charts are the most important charts as anyone with good eyesight can determine whether something is in focus or not, however, judging slight changes in colour tone is far more subjective.
As described by Marc Spiwak in his 2011 article for inDepth, there are several colour charting devices that can be used to measure colours in a video signal, using the Vectorscope device. The most popular being the SMPTE colour bar signal feed.
“A vectorscope is a special type of oscilloscope that displays a graphical representation of the colours present in an image, and their intensities. A vectorscope has a circular display surrounding six boxes, each representing yellow, green, cyan, blue and magenta. When you feed a video signal into a vectorscope, dots representing each colour that are present in the signal will fall into place in the rough shape of a hexagon, within the circular display.
The SMPTE colour bars are a signal that’s fed to TVs and monitors to check their colour displays. When you feed the SMPTE colour bar signal into a vectorscope, a dot should fall into place within each box representing the yellow, green, cyan, blue and magenta colours present in the signal. White, black and grey all generate a dot in the centre of the display because those signals contain no colour information. The distance from the centre of the display to each of the colour dots represents the intensity, or saturation of each colour. If the dots don’t fall into the centre of each colour box, the video signal does not accurately represent the colours it’s supposed to, meaning the lighting was off, settings on the camera were made improperly or the camera was not functioning properly.”
To improve your video production quality, NoStairway Media suggest that you shoot a colour chart for a few seconds at the beginning of each take, so every colour in every scene is a perfect match. To make this a sure success, make sure all the colours you will be working with are present on the chart aka different shades of skin tones. So come on guys Lets get Creative!
