The Pixel Puzzle
Vision systems and video standards are complex. At a consumer level we are bombarded with technical specifications in an attempt to sell the latest and greatest. At an events level we are producing bigger and better digital content and pushing the boundaries of available technologies. While this is an extremely technical and complicated field I have attempted to provide an overview of some common terms and standards without being overly technical.
In general, a pixel can be defined as the smallest single component of a digital image. It is not a fixed unit of measurement, like a centimetre or a metre, and is somewhat dependent on context such as in print, digital cameras or digital displays as to its manifestation as an output. To complicate things even further a pixel can also be used unit of measurement, this is more common in web development and we won’t go into detail this time.
In digital displays each pixel is made up of three colour filters; red, green and blue (additive colour).
It is worth briefly touching on colour models to understand how they relate to digital displays and printing.
RGB (Red, Green and Blue) is an additive colour model used for all digital displays. When the three colours are combined as emitted light they are visible as white. Black is the absence of any colour.
CMYK (Cyan, Magenta, Yellow and Black) is a subtractive colour model used for all printing. When the three colours are combined as reflected light they are visible as black. White is the absence any colour.
It is important to note that an ‘aspect ratio’ is a separate measurement to screen resolution, although they are inherently linked. In very simple terms a ratio is the relationship between two quantities, for example: 1 cup of rice to 2 cups of water = a 1:2 ratio.
Since around 2009, the most common aspect ratio for display devices is 16:9, as close a ‘standard’ as is likely to exist, your computer monitor and your home LCD TV are examples. The ratio simply means that for every 16 pixels horizontally there will be 9 vertically.
Prior to the 16:9 standardisation the old televisions sets had an aspect ratio of 4:3, a much squarer display.
The most widely accepted screen resolution for modern display devices is 1920 x 1080 pixels. This standard in commonly known as Full-HD and is a 16:9 aspect ratio.
Display resolution is the width and height dimensions of a display device in pixels. It is not a measurement of physical size. A good example is the comparison of an iPhone to an LCD TV screen:
• An iPhone 7 Plus has a screen resolution of 1920 x 1080 pixels in a physical screen size of 12.2cm x 6.8cm (landscape)
• A 40” LCD TV screen has a resolution of 1920 x 1080 pixels in a physical screen size of 93cm x 52cm
This means that each pixels on the 40” screen is larger than each pixel on the iPhone and as such the images are not seen as sharply or as detailed as on the iPhone screen.
As technology does, new and improved display resolutions are rapidly becoming adopted. The next standard in known as 4K (or Ultra-HD), a display resolution of around 4000 x 2000 pixels. It is estimated that by 2025 more half all consumer screens will be 4K, a significantly faster adoption rate than Full-HD.
Put simply, the more pixels you have the higher the resolution.
There are many other technical standards that further describe the complex world of vision systems and video standards, but understanding the basic terms and the ‘standards’ will be of great assistance when dealing with content devolvement, AV suppliers and even buying a new TV.
Dylan McLaughlin – Producer