To back up to that sheet of paper "nonsense" as you call it, Steve - there's more than one reason
for using a very accurate grain magnifier. For one thing, I print some very big polyester prints, and
nobody is going to confuse them with a damn fuzzy inkjet or even Lightjet. Sometimes I need to
enlarge a 4X5 or smaller original onto an 8x10 dupe chrome or interneg. There is a very precise vac
filmholder involved, carefully selected apo graphics lenses, and meticulous alignment of everything.
When that gets enlarged to a 30x40 print, not only would the hypothetical thickness of paper matter, but rather, I focus upon a sheet of film exactly the same thickness. Otherwise a lot of time
and money would go down the drain! This illustrates the principle involved. Just because typical fiber
based papers can't always reproduce that level of detail does not mean thickness is not an actual
factor!