Color depth also known as bit depth is the number of bites used to indicate the color of a single pixel in an image or video. It ranges from 1bit or monochrome to a whopping 48-bit color or 281 trillions of colors.
One bit images are known as monochrome images and only show white and black (2 ^ 1), two bit images have also shades of those color, and only at 8 bits, the basic colors show. To achieve a vivid image with all the colors that an untrained eye can see, you will need at least 16bit of color depth.
The problem that gets in the way of all of us having a 48bit display is that every link of the chain needs to be high-quality. The first link that usually gets broken is the storage medium. A 48 bit image is a pretty big one, considering that a 10MP image needs around 60MB of storage. If you consider that in a movie there are around 30 images a second, you will need a drive big enough to store a movie and fast enough to read everything in order not to buffer at every frame.
Another problem would be the cost of the displays and the power needed to push those pixels. Another big problem would be the speed of the internet, as you will need around 200MB a second to watch a movie at this bit depth online.
The biggest problem will be infrastructure, as streaming this kind of files will put a really serious strain on every part of the infrastructure, at least for time of writing this.
To put things in perspective, you will not see the downsides of a lower bit depth image where the colors are different. You will see them where the colors are very similar, for example in shaded shots.
I really wanted to cover this topic to be able to say something. Resolution is just a number, you can have a movie that is 1080p but with 10bit color depth, and it will look worse than a 480p movie with 16bit or greater bit depth. So next time when someone asks you why there “HD” image is not looking good enough, at least you will know what the problem is. Thanks for reading!