Do you know what is width of paper? Width of paper sounds like something esoteric. And what is the definition of width of paper?
We know that different paper have different sizes, but what is width of paper in common?
Width of paper are different from each other, The size of A4 is 210mm*297mm, that is 21.0cm*29.7cm. 1 inch equals 2.54cm. when the resolution is 72 pixels per inch, when we convert it into centimeter, the conversion would be 28.3 pixels/cm. when we convert it to image it will be (21*28.3)8(29.7*28.3), that is: 595*842( in pixels)
In the same way, we can get this: when resolution is 300 pixels per inch, the size of A4 would be 2479*3508. When resolution Is pixels per inch, the size of A4 would be 1487*2105 pixels.
When we printing the pictures, we had better to conversion first, otherwise it may reduce the quality of the images.
In general, if it is printed, it is best to use 300 pixels per inch, if the printer is painting, we can choose a resolution of 72 pixels per inch. So we have know the width of paper now.