I was curious to know if printing questions in regards to how the design turns out on topic here and what would possibly render the question off-topic? I know I shouldn't ask about equipment but if I wanted to ask a question in regards to the type of median used for a desired design look on topic?
I think any sort of prepress questions are fine here. As an example: "How should I set up a two color silkscreen print with trapping?" makes sense to me to be within the scope of Graphic Design.
However, technical printing questions are their own realm and don't fit here. For example: "How can I achieve tight registration for a multicolor silkscreen job that has trapping?" would stick out as something beyond the scope of GD.
To address your example specifically (type of medium for a desired design look)—that sounds on topic to me.
I think printing questions are perfectly fine as long as they have a bit of GD in them. So asking about printing issues/details that arise from or can be affected by graphics design are okay. E.g. How to do GD for ABCD with regard to printing issues EFGH?.
Purely printing questions are a bit offtopic IMO. E.g. How to load paper into bin to achieve best alignment? or In which order to silk-screen colors?. But still they are connected with GD and provide some in-depth view on the process and IMHO they could be tolerated.