In my most recent struggle, I was at Staples asking about what thickness of paper to use for my short story - as the person helping me explains that it is totally up to me and there are many different thickness and textures to each paper and to feel them and choose the one I want.
Needless to say, it did not help much and I ended up having to use my own judgement. In fact, this same question came up TODAY before I went to buy a large pack of papers to start folding for my book.
I remembered Jess saying that 32b is good for the inside because it is thicker than generic 20lb thicker paper, but won't bleed through the other side. As I work with this paper I can definitely see the difference.
From my experience, it seems you really have to use your own judgement, work with different thickness and textures, and do lots of printing samples before you find exactly what you want to use.
Here is a little scale of paper thickness from thinnest to thickest:
I can't tell if this is legible - but the lightest paper is super thin at 9 lb. and the heaviest paper is super thick at 130 lb.
HUGE DIFFERENCES!! Before becoming a designer, never in my life would I be thinking about how big and important the paper world actually is.
