When evaluating a four-color printing machine, you must prioritize the maximum printing speed (measured in sheets per hour or meters per minute) and the maximum printing width/format to ensure it meets your production capacity. Pay close attention to the registration accuracy (ideally within ±0.1mm) to ensure high-quality color alignment. Additionally, verify the drying system type (UV, IR, or hot air) as this directly impacts the turnaround time and the types of substrates (paper, plastic, or film) you can process.