Traditional Culture Encyclopedia - Photography major - What does the picture number k mean?

What does the picture number k mean?

This refers to the pixel size. It's usually the size of this picture.

Because you want to print large pixels. This is the decision of printing itself. At present, the printed DPI means that the resolution needs to be 300 to print clearly.

The pictures displayed on the Internet are all 72DPI, so it will be unclear when printed.