According to the size of A4 paper as 2 10 mm× 297 mm and 1 inch =2.54 cm, we can get the size of A4 paper when the resolution is several pixels. The following are the specifications and sizes we have used for a long time:

When the resolution is 72 pixels/inch, the length, width and pixels of A4 paper are 842× 595 respectively.

When the resolution is 120 pixels/inch, the length and width pixels of A4 paper are 2105×1487 respectively;

When the resolution is 150 pixels/inch, the length and width pixels of A4 paper are1754×1240 respectively;

When the resolution is 300 pixels/inch, the length, width and pixels of A4 paper are 3508× 2479 respectively.

Therefore, you can cut the background material according to the standard pixels and aspect ratio.