Same magnification than the one used to see Acari (x200 approximately)
It would nice to put an Acari on this surface and to directly compare. Next time.
Dots per inch or pixels per inch. This is the number of printed points used to print a newspaper for example. No surprise: we cannot distinguish these dots or pixels with our eyes. This is done on purpose : images look smooth. x200 USB Microscope can easily overcome our eye limit and reveals the dot structure. On a picture taken on a magazine image, dots are easily identified.
Common values for personal printers are 300 dpi and higher. 1200 dpi laser printer are available.
100 dpi corresponds more or les to a pixel of 250 micrometer or 0,25mm.