A 4K Primer
4K refers to the number of pixels (approximately 4000) across a frame of film or digital image.
To convert a frame of film into digital format, it is scanned a particular horizontal resolution limited by the number of pixel elements across the imager. "2K" resolution is equivalent to approximately 2000 pixels; "4K" is approximately 4000 pixels. All things being equal, the higher the resolution, the more detail can be extracted from the film.
The line scanning approach to scanning film has its roots in the world of machine vision and industrial inspection (DALSA has a 25+ year history in the field, and, in fact, developed the first broadly used 4K line scan image sensor back in the 1980s—read more about “DALSA & 4K”). The film moves past a line of pixels, which build up a continuous image—a fax machine is a crude example. Line scanning has been proven to be a cost effective and efficient method for scanning film, but it obviously doesn't help much on a movie set.
With the advent of digital cameras that are designed to replace film and film scanning, the principles of 2K and 4K still apply. That is, the resolution of the resulting digital image, whether it started on film or in the digital realm, can still be described in terms of 2K or 4K resolution. Note that 4K isn't just twice as much resolution as 2K—4K is twice as wide and twice as high, and therefore 4K has four times the resolution of 2K.
But, is 4K just about the resolution
Pixel count tends to dominate discussions of digital imaging, but it shouldn't. Is resolution the only quality factor to consider? We don’t think so. Scanning film at 4K resolution with a low quality image sensor chip, like one from a fax machine, will provide inferior image quality with excessive noise, loss of tonal detail, poor color fidelity, and so on. The situation is the same for digital cameras—if you start with mediocre pixels, even millions of them won't give you a good image.
DALSA has learned through decades of development and experience in high performance digital imaging how to combine high resolution with high dynamic range to produce images that have not only a high level of detail but also remarkable exposure latitude. With so much exposure latitude, our 4K cameras can digitize at higher precision than any others and output higher bit depth data (16 bit linear) for the very best image quality.
