Lulu does nothing, they're just a middleman. The actual printing is done by ColorCentricCorp. Lulu hosts the pdfs, waits until they have some minimum total order and sends it off to CCC, who then print it, ship it to Lulu, and Lulu ships it to whoever ordered it.
That's why they're expensive, slow, and know very little about the various printing options and requirements - they're middlemen.
-Kyle Aaron on theRPGsite
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