Answers to printing basics

Film is a film, an indispensable part of printing. The key step in turning computer's digital information into physical information. However, now that digital printing is just around the corner, I believe that it will not be long before the film will be retired. Assuming that it is doing the cover of the magazine, but after finishing the printing field, it cannot be printed. The resolution is too low; the default is 72DPI. Later I knew not, but what is the actual DPI?
Scanning Resolution (dpi) = Number of Screening Lines (lpi) × Magnification Newspaper: 85 lpi
Color Magazine: 133,150 or 175 lpi
Art album: 200lpi
It is sufficient to set the cover of the general book to 300-350 dpi.
In PS, an image size is 103MM x 103MM (including bleeding)
The corner line is a spot color, 103mm, corner line is set color (that is, 4 colors)
When converting RGB to CMYK, there is a big difference in the colors between photoshop and acdsee. Where is the color after printing? Close to photoshop, but not exactly.
Monochrome if the BITMAP format is recommended at least 1000DPI, if the gray is 300 enough; 150dpi to do more printing press, copper plated also 300dpi.
Overprinting, overprinting, and trapping: Overprinting is the first printing of a color, and the printing of another one on the trapping trap: the place where the two colors meet may be shifted in printing when not trapped. White edge or color aliasing occurs. The trapping is to infiltrate with the two colors of the transfer at the place of transfer, and no white border will be produced.