Briefly describe the similarities and differences between mechanical proofing and digital proofing?

The proofing of offset press needs film production and plate making, which is costly and time-consuming. Digital proofing time is short, no film is needed, no plate making is needed, and the cost is low. If the goods printed in batch are offset printing, it is of course closer to the offset printing proofing of large goods. If you use digital proofing and offset printing to print large goods, there may be color difference, because offset printing and digital printing are not a printing method.