At this point, they're usually green because they're usually green. It's the most common mask color, therefore the cheapest. Also, oddly enough, not only do dif

At this point, they're usually green because they're usually green. It's the most common mask color, therefore the cheapest. Also, oddly enough, not only do different mask colors have different achievable resolutions (minimum line widths) - some colors don't stick to the PCB as well!