if the resolution of a printer is 1200 dpi the number of dots per square inch is
Dots per inch Dots per inch (DPI, or dpi)[1] is a measure of spatial printing or video or image scanner dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch (2.54 cm).
Book size These various production methods are referred to as the format of the book. These terms are often abbreviated, using 4to for quarto, 8vo for octavo, and so on. The octavo format, with eight leaves per gathering, has half the page size of the quarto format before trimming. Smaller formats include the duodecimo (or twelvemo), with twelve leaves per sheet and pages one-third the size of the quarto format, and the sextodecimo (or sixteenmo), with sixteen leaves per sheet, half the size of the octavo format and one quarter the size of the quarto. The vast majority of books were printed in the folio, quarto, octavo or duodecimo formats.[4]:82