Thanks for the info.
I can't be the only person who is still confuzzled.
I interpret stuff like this as "clearer picture, improved coloration, better sound quality."
I might need it explained in idiot terms.
Technically 4K is just referring to resolution. Colour and sound quality are separate (though they do tend to all scale up together).
Resolution is clarity of picture, which is made up of pixels (light dots, effectively). If you have a 32" screen, then DVD quality is 720x576 (pal), which gives 414,720 dots, full HD is 1980x1080 which is 2,073,600 dots, and 4K (UHD) is 3840x2160 so 8,294,400 dots. The more dots available per inch, the greater the clarity of image.
Colouration and depth depends on bandwidth, which is set as part of a standard set for what is supported in specific media (i.e DVD, blu ray, UHD blu ray, etc). The more bandwidth (space) available, the greater the depth of video and audio quality available up until lossless (which is where were at now), when you can then get no greater quality, but can expand channels. Resolution is also a part of the standard, and multiple resolutions can be supported in each standard, which is why you can get standard definition special features on an HD blu ray.