1) We want analogue prints, not inkjet prints. Check!
However, an analogue print doesn't have to be on silver based photographic paper only. Thus all alt-photo procedures like, gum printing, casein printing cyanotype, carbon printing (as invented by Alphonse Poitevin in 1855, not laserprinting), salt printing, etc. are eligible, IF:
2) the original image/negative was made in an analogue way. So, not an image made with an Iphone, worked over in Photoshop and digital printed as a negative.
Shortly: If you can find the printing process in this wonderful & must read book, it is allowed (IMHO):
You'll get the drift ....