When using alternative printing methods, it is important to make sure that the overprint effect between green and black is maintained. The rule is that when overprinting a green track on a black path, the path must be visible through the green, and not totally cleared out. When printing offset, green is the last colour ("overprint") and this effect is automatically achieved, but when using digital methods this effect must be controlled through the software.
Please refer also to section 3.4 Printing, in this publication.